What is the typical age of onset for male pattern baldness?
Asim Shahmalak
He is a frequent media spokesman, and has written about the importance placed in hair over the centuries and the fact that baldness until recently was not recognised as a social or medical issue, despite the sometimes catastrophic impact it can have on confidence and mental well-being. He wrote: "Male pattern baldness (MPB), the main cause of hair loss, affects an estimated quarter of men by the age of 30 and two thirds by the age of 60. Until recently, the impact baldness might have on confidence and well-being was little understood or recognised by the medical profession at large."
Migraine
These figures vary substantially with age: migraines most commonly start between 15 and 24 years of age and occur most frequently in those 35 to 45 years of age. In children, about 1.7% of 7 year olds and 3.9% of those between 7 and 15 years have migraines, with the condition being slightly more common in boys before puberty. During adolescence migraines become more common among women and this persists for the rest of the lifespan, being two times more common among elderly females than males. In women migraines without aura are more common than migraines with aura, however in men the two types occur with similar frequency.
During perimenopause symptoms often get worse before decreasing in severity. While symptoms resolve in about two thirds of the elderly, in between 3 and 10% they persist.
5α-Reductase deficiency
In adulthood, individuals do not experience male-pattern baldness. As dihydrotestosterone (DHT) is a far more potent androgen than testosterone alone, virilization in those lacking DHT may be absent or reduced compared to males with functional 5-AR. It is hypothesized that rising testosterone levels at the start of puberty are able to generate sufficient levels of DHT either by the action of 5α-reductase type I (active in the adult liver, non-genital skin and some brain areas) or through the expression of low levels of 5α-reductase type II in the testes.
Pattern hair loss
Proposed social theories for male-pattern hair loss include that baldness signaled dominance, social status, or longevity. Biologists have hypothesized the larger sunlight exposed area would allow more vitamin D to be synthesized, which might have been a "finely tuned mechanism to prevent prostate cancer", as the malignancy itself is also associated with higher levels of DHT. However, this argument is weak considering the fact that baldness is very rare in East Asians. As well, early hominins such as the Neandertals do not possess any of the balding variants on the various association loci, who presumably would have been under positive selection for increased Vitamin D synthesis.
Human hair color
Changes in hair color typically occur naturally as people age, eventually turning the hair gray and then white. This is called achromotrichia. Achromotrichia normally begins in the early to mid-twenties in men and late twenties in women. More than 60 percent of Americans have some gray hair by age 40. The age at which graying begins seems almost entirely due to genetics. Sometimes people are born with gray hair because they inherit the trait.
Pubarche
During puberty pubarche tends to occur earlier in girls than boys, as with most puberty stages and puberty as a whole. The average age for females varies between 12-14, and for males, about 13-15.
Schizophreniform disorder
Schizophreniform disorder is equally prevalent among men and women. The most common ages of onset are 18–24 for men and 18–35 for women. While the symptoms of schizophrenia often develop gradually over a period of years, the diagnostic criteria for schizophreniform disorder require a much more rapid onset.
Satoyoshi syndrome
People with the syndrome typically develop symptoms of the illness at a young age, usually between the age of six and fifteen years old. The initial symptoms are muscle spasms in the legs and alopecia, also known as baldness. The spasms are painful and progressive and their frequency varies from 1 or 2 to 100 per day, each lasting a few minutes. It can be sufficiently severe to produce abnormal posturing of the affected limbs, particularly the thumbs. With progression the illness involves the pectoral girdle and trunk muscles and finally the masseters and temporal muscles. The spasms usually spare the facial muscles. Severe spasms can interfere with respiration and speech. During an attack-free period, non-stimulus-sensitive myoclonus can occur in the arms, legs and neck. Diarrhea occurs in the first 2–3 years with intolerance to carbohydrate and high glucose diets. Endocrinopathy manifests as amenorrhea and hypoplasia of the uterus. Affected children fail to attain height after 10–12 years of age.
Lalit Goel
In NTU, his students remembered him for his style of teaching, as well as his distinctive moustache and bald pate. He had started losing his hair from the age of 18; according to him, the baldness might be hereditary.
Pattern hair loss
Pattern hair loss, known as male-pattern hair loss (MPHL) when it affects males and female-pattern hair loss (FPHL) when it affects females, is hair loss that primarily affects the top and front of the scalp. In males, the hair loss often presents as a receding hairline, while in females, it typically presents as a thinning of the hair.
Male pattern hair loss is believed to be due to a combination of genetics and the male hormone dihydrotestosterone. The cause in female pattern hair loss remains unclear.
Management may include simply accepting the condition. Otherwise, treatments may include minoxidil, finasteride, or hair transplant surgery. Evidence for finasteride in women, however, is poor and it may result in birth defects if taken during pregnancy.
Pattern hair loss by the age of 50 affects about half of males and a quarter of females. It is the most common cause of hair loss. 
Classic male-pattern hair loss begins above the temples and vertex (calvaria) of the scalp. As it progresses, a rim of hair at the sides and rear of the head remains. This has been referred to as a 'Hippocratic wreath', and rarely progresses to complete baldness. Pattern hair loss is classified as a form of non-scarring hair loss. The Hamilton–Norwood scale has been developed to grade androgenic alopecia in males.
Ménétrier's disease
The average age of onset is 40 to 60 years, and men are affected more often than women. Adults with Ménétrier disease have a higher risk of developing gastric adenocarcinoma.
Diabetes mellitus and deafness
MIDD represents 1% of people who have diabetes. Over 85% of people that carry the mutation in mitochondrial DNA at position 3243 present symptoms of diabetes. The average age at which people who have MIDD are typically diagnosed is 37 years old but has been seen to range anywhere between 11 years to 68 years old. Of these people with diabetes carrying the mitochondrial DNA mutation at position 3243, 75% experience sensorineural hearing loss. In these cases, hearing loss normally appears before the onset of diabetes and is marked by a decrease in perception of high tone frequencies. The associated hearing loss with diabetes is typically more common and more quickly declining in men than in women.
Schizophrenia
Schizophrenia affects around 0.3–0.7% of people at some point in their life, or 24 million people worldwide as of 2011. It occurs 1.4 times more frequently in males than females and typically appears earlier in men—the peak ages of onset are 25 years for males and 27 years for females. Onset in childhood is much rarer, as is onset in middle or old age.
Eating disorders and development
Similar to anorexia, bulimia typically begins during adolescence, though the average age of onset is somewhat later than that of anorexia. Onset before puberty and after age 40 is atypical.
Pattern hair loss
The fact that hair loss is cumulative with age while androgen levels fall as well as the fact that finasteride does not reverse advanced stages of androgenetic alopecia remains a mystery but some possible explanations have been put forward: Higher conversion of testosterone to DHT locally with age as higher levels of 5-alpha reductase are noted in balding scalp, and higher levels of DNA damage in the dermal papilla as well as senescence of the dermal papilla due to androgen receptor activation and environmental stress. The mechanism by which the androgen receptor triggers dermal papilla permanent senescence is not known but may involve IL6, TGFB-1 and oxidative stress. Senescence of the dermal papilla is measured by lack of mobility, different size and shape, lower replication and altered output of molecules and different expression of markers. The dermal papilla is the primary location of androgen action and its migration towards the hair bulge and subsequent signaling and size increase are required to maintain the hair follicle so senescence via the androgen receptor explains much of the physiology.
Congenital adrenal hyperplasia
Males with classic CAH generally have no signs of CAH at birth. Some may present with hyperpigmentation, due to co-secretion with melanocyte-stimulating hormone (MSH), and possible penile enlargement. Age of diagnosis of males with CAH varies and depends on the severity of aldosterone deficiency. Boys with salt-wasting disease present early with symptoms of hyponatremia and hypovolemia. Boys with non-salt-wasting disease present later with signs of virilization.
Adolescence
The major landmark of puberty for males is spermarche, the first ejaculation, which occurs, on average, at age 13. For females, it is menarche, the onset of menstruation, which occurs, on average, between ages 12 and 13. The age of menarche is influenced by heredity, but a girl's diet and lifestyle contribute as well. Regardless of genes, a girl must have a certain proportion of body fat to attain menarche. Consequently, girls who have a high-fat diet and who are not physically active begin menstruating earlier, on average, than girls whose diet contains less fat and whose activities involve fat reducing exercise (e.g. ballet and gymnastics). Girls who experience malnutrition or are in societies in which children are expected to perform physical labor also begin menstruating at later ages.
Pattern hair loss
The only published study to test correlation between ejaculation frequency and baldness was probably large enough to detect an association (1390 subjects) and found no correlation, although persons with only vertex androgenetic alopecia had fewer female sexual partners than those of other androgenetic alopecia categories (such as frontal or both frontal and vertex). One study may not be enough, especially in baldness, where there is a complex with age. Marital status has been shown in some studies to influence hair loss in cross-sectional studies (NHANES1), although the direction of effect cannot be inferred from a cross sectional study.
Rolandic epilepsy
The age of onset ranges from 1 to 14 years with 75% starting between 7–10 years. There is a 1.5 male predominance, prevalence is around 15% in children aged 1–15 years with non-febrile seizures and incidence is 10–20/100,000 of children aged 0–15 years
Irritable male syndrome
The term was popularized by author Jed Diamond in 2004 as being related to "andropause", a concept he had earlier popularized. According to Diamond, andropause is a change of life in middle-aged men, which has hormonal, physical, psychological, interpersonal, social, sexual, and spiritual aspects. He says that this change occurs in all men, may occur as early as age 45 to 50 and more dramatically after the age of 70 in some men, and that women's and men's experiences are somewhat similar phenomena.
Down syndrome
Down syndrome (DS or DNS), also known as trisomy 21, is a genetic disorder caused by the presence of all or part of a third copy of chromosome 21. It is typically associated with physical growth delays, mild to moderate intellectual disability, and characteristic facial features. The average IQ of a young adult with Down syndrome is 50, equivalent to the mental ability of an 8- or 9-year-old child, but this can vary widely.
The parents of the affected individual are typically genetically normal. The probability increases from less than 0.1% in 20-year-old mothers to 3% in those age 45. The extra chromosome is believed to occur by chance, with no known behavioral activity or environmental factor that changes the probability. Down syndrome can be identified during pregnancy by prenatal screening followed by diagnostic testing or after birth by direct observation and genetic testing. Since the introduction of screening, pregnancies with the diagnosis are often terminated. Regular screening for health problems common in Down syndrome is recommended throughout the person's life.
There is no cure for Down syndrome. Education and proper care have been shown to improve quality of life. Some children with Down syndrome are educated in typical school classes, while others require more specialized education. Some individuals with Down syndrome graduate from high school, and a few attend post-secondary education. In adulthood, about 20% in the United States do paid work in some capacity, with many requiring a sheltered work environment. Support in financial and legal matters is often needed. Life expectancy is around 50 to 60 years in the developed world with proper health care.
Down syndrome is one of the most common chromosome abnormalities in humans. It occurs in about one per 1,000 babies born each year. In 2015, Down syndrome was present in 5.4 million individuals globally and resulted in 27,000 deaths, down from 43,000 deaths in 1990. It is named after John Langdon Down, a British doctor who fully described the syndrome in 1866. Some aspects of the condition were described earlier by Jean-Étienne Dominique Esquirol in 1838 and Édouard Séguin in 1844. In 1959, the genetic cause of Down syndrome, an extra copy of chromosome 21, was discovered.
Those with Down syndrome nearly always have physical and intellectual disabilities. As adults, their mental abilities are typically similar to those of an 8- or 9-year-old. They also typically have poor immune function and generally reach developmental milestones at a later age. They have an increased risk of a number of other health problems, including congenital heart defect, epilepsy, leukemia, thyroid diseases, and mental disorders.
Age of onset
The age of onset is the age at which an individual acquires, develops, or first experiences a condition or symptoms of a disease or disorder. For instance, the general age of onset for the spinal disease scoliosis is "10-15 years old," meaning that most people develop scoliosis when they are of an age between ten and fifteen years.
Down syndrome
Males with Down syndrome usually do not father children, while females have lower rates of fertility relative to those who are unaffected. Fertility is estimated to be present in 30–50% of females. Menopause typically occurs at an earlier age. The poor fertility in males is thought to be due to problems with sperm development; however, it may also be related to not being sexually active. As of 2006, three instances of males with Down syndrome fathering children and 26 cases of females having children have been reported. Without assisted reproductive technologies, around half of the children of someone with Down syndrome will also have the syndrome.
Congenital adrenal hyperplasia due to 21-hydroxylase deficiency
Appearance of pubic hair in mid-childhood is the most common feature that leads to evaluation and diagnosis. Other accompanying features are likely to be tall stature and accelerated bone age (often 3–5 years ahead). Often present are increased muscle mass, acne, and adult body odor. In boys the penis will be enlarged. Mild clitoral enlargement may occur in girls, and sometimes a degree of prenatal virilization is recognized that may have gone unnoticed in infancy.
Appendicitis
Appendicitis is most common between the ages of 5 and 40; the median age is 28. Risk factors include being male, higher household income and living in a rural area. In 2013 it resulted in 72,000 deaths globally down from 88,000 in 1990.
Puberty
Research by Øster (1968) found that with the onset and continuation of puberty, the proportion of boys able to pull back their foreskins increased. At ages 12–13, Øster found that only 60% of boys were able to retract their foreskins; this increased to 85% by ages 14–15, and 95% by 16–17. He also found that 1% of those unable to fully retract experienced phimosis at ages 14–17, the remainder were partially able to. The findings were supported by further research by Kayaba "et al" (1996) on a sample of over 600 boys, and Ishikawa and Kawakita (2004) found that by age 15, 77% of their sample of boys could retract their foreskins. Beaugé (1997) reports that boys may assist the development of retractile foreskin by manual stretching.
Indo-Pacific humpbacked dolphin
Calves and juveniles less than a year old are typically unspotted and bear a grey coloration. Subadults slowly develop a "mottled" or "speckled" coating between the ages of 4 and 20, with females experiencing an earlier onset of this pattern development compared to males. After the age of 25, adults begin to slowly lose this spotted pattern and, once again, females experience an earlier onset and drastically faster rate of loss when compared to males.
Stuttering
The lifetime prevalence, or the proportion of individuals expected to stutter at one time in their lives, is about 5%, and overall males are affected two to five times more often than females. However, there is not much information known about the underlying cause for such a skewed sex ratio. Most stuttering begins in early childhood, and studies suggest that 2.5% of children under the age of 5 stutter. As seen in children who have just begun stuttering, there is an equivalent number of boys and girls who stutter. Still, the sex ratio appears to widen as children grow: among preschoolers, boys who stutter outnumber girls who stutter by about a two to one ratio, or less. This ratio widens to three to one during first grade, and five to one during fifth grade, as girls have higher recovery rates. Due to high (approximately 65–75%) rates of early recovery, the overall prevalence of stuttering is generally considered to be approximately 1%.
Adie syndrome
It most commonly affects younger women (2.6:1 female preponderance) and is unilateral in 80% of cases. Average age of onset is 32 years.
Hoarse voice
There is an interplay of sex and age differences associated with dysphonia. The point prevalence of dysphonia in adults under the age of 65 is 6.6%. Dysphonia is more common in adult females than males, possibly due to sex-related anatomical differences of the vocal mechanism. In childhood, however, dysphonia is more often found in boys than girls. As there are no anatomical differences in larynges of boys and girls prior to puberty, it has been proposed that the higher rate of voice impairment found in boys arises from louder social activities, personality factors, or more frequent inappropriate vocal use. The most common laryngeal diagnosis among children is vocal fold nodules, a condition known to be associated with vocally damaging behaviours. However, a causal relationship has not yet been definitively proven. The overall prevalence of dysphonia in children ranges from 3.9% - 23.4%, most commonly affecting children between the ages of 8 - 14. Among the elderly, dysphonia is associated with both naturally occurring anatomical and physiological changes as well as higher rates of pathological conditions. The point prevalence of dysphonia among the elderly is 29%. Findings regarding the prevalence of geriatric dysphonia in the general population are very variable, ranging from 4 - 29.1%. This variability is likely due to different methodology used in obtaining information from participants. The most common laryngeal diagnoses among the elderly are polyps, laryngopharyngeal reflux, muscle tension dysphonia, vocal fold paresis or paralysis, vocal fold mass, glottic insufficiency, malignant lesions, and neurologic conditions affecting the larynx.
Hair loss
Symptoms of hair loss include hair loss in patches usually in circular patterns, dandruff, skin lesions, and scarring. Alopecia areata (mild – medium level) usually shows in unusual hair loss areas, e.g., eyebrows, backside of the head or above the ears, areas the male pattern baldness usually does not affect. In male-pattern hair loss, loss and thinning begin at the temples and the crown and hair either thins out or falls out. Female-pattern hair loss occurs at the frontal and parietal.
Mal de debarquement
Subsequent studies have produced conflicting results with regard to the gender distribution of MdDS. The trends in Hain's report have recently been supported by the MdDS Balance Disorder Foundation, in a study of over 100 individuals diagnosed with MdDS. The female:male ratio was approximately 9:1; the average age of onset was 43–45 years. However, another recent study found that 44% of subjects who had experienced MdDS for 2 years or more were male, suggesting a more even distribution.
Thyrotoxic periodic paralysis
The typical age of onset is 20–40. It is unknown why males are predominantly affected, with rates in males being 17- to 70-fold those in females, despite thyroid overactivity being much more common in women.
Pattern hair loss
Studies have been inconsistent and not stable across cultures how balding men rate on the attraction scale. While a study from South Korea showed most people rated balding men as less attractive, a more recent survey of 1,000 Welsh women rated bald and gray haired men quite desirable.
Stafne defect
Stafne defect is uncommon, and has been reported to develop anywhere between the ages of 11 and 30 years old, (although the defect is developmental, it does not seem to be present form birth, implying that the lesion develops at a later age). Usually the defect is unilateral (on one side only) and most commonly occurs in men.
Setipiprant
However, following the discovery in 2012 that the prostaglandin D receptor (DP/PGD) is expressed at high levels in the scalp of men affected by male pattern baldness, the rights to setipiprant were acquired by Kythera to develop the drug as a novel treatment for baldness. The favorable pharmacokinetics and relative lack of side effects seen in earlier clinical trials mean that fresh clinical trials for this new application can be conducted fairly quickly. , setipiprant is currently under development by Allergan for the prevention of androgenic alopecia after their successful acquisition of Kythera.
Finasteride
Finasteride is also used to treat male pattern baldness (androgenetic alopecia) in men, a condition that develops in up to 80% of Caucasian men. In the United States, finasteride and minoxidil are the only two FDA approved drugs for the treatment of male pattern hair loss as of 2017. Treatment with finasteride slows further hair loss and provides about 30% improvement in hair loss after six months of treatment, with effectiveness persisting as long as the drug is taken. Taking finasteride leads to a reduction in scalp and serum DHT levels; by lowering scalp levels of DHT, finasteride can maintain or increase the amount of terminal hairs in the anagen phase by inhibiting and sometimes reversing miniaturization of the hair follicle. Finasteride is most effective on the vertex but can reduce hair loss in all areas of the scalp. Finasteride has also been tested for pattern hair loss in women; however, the results were no better than placebo.
Rapid eye movement sleep behavior disorder
RBD prevalence as of 2017 is estimated to be 0.5–2% overall, and 5–13% of those aged 60 to 99. It is more common in males overall, but equally frequent among men and women below the age of 50. This may partially be due to a referral bias, as violent activity carried out by men is more likely to result in harm and injury and is more likely to be reported than injury to male bed partners by women, or it may reflect a true difference in prevalence as a result of genetic or androgenic factors. Typical onset is in the 50s or 60s.
Corticobasal degeneration
Clinical presentation of CBgD usually does not occur until age 60, with the earliest recorded diagnosis and subsequent postmortem verification being age 28. Although men and women present with the disease, some analysis has shown a predominant appearance of CBD in women. Current calculations suggest that the prevalence of CBgD is approximately 4.9 to 7.3 per 100,000 people. The prognosis for an individual diagnosed with CBgD is death within approximately eight years, although some patients have been diagnosed over 17 years ago (2017) and are still in relatively good standing, but with serious debilitation such as dysphagia, and overall limb rigidity. The partial (or total) use of a feeding tube may be necessary and will help prevent aspiration pneumonia, primary cause of death in CBgD. Incontinence is common, as patients often can't express their need to go, due to eventual loss of speech. Therefore, proper hygiene is mandatory to prevent urinary tract infections.
Primary sclerosing cholangitis
There is a 2-3:1 male-to-female predilection in primary sclerosing cholangitis. PSC can affect men and women at any age, although it is commonly diagnosed in the fourth decade of life, most often in the presence of inflammatory bowel disease (IBD). PSC progresses slowly and is often asymptomatic, so it can be present for years before it is diagnosed and before it causes clinically significant consequences. There is relatively little data on the prevalence and incidence of primary sclerosing cholangitis, with studies in different countries showing annual incidence of 0.068–1.3 per 100,000 people and prevalence 0.22–8.5 per 100,000; given that PSC is closely linked with ulcerative colitis, it is likely that the risk is higher in populations where UC is more common. In the United States, an estimated 29,000 individuals have PSC.
Demyelinating disease
Incidence of demyelinating diseases vary from disorder to disorder. Some conditions, such as Tabes dorsalis appear predominantly in males and begins in mid-life. Optic neuritis on the other hand, occurs preferentially in females typically between the ages of 30 and 35. Other conditions such as multiple sclerosis vary in prevalence depending on the country and population. This condition can appear in children as well as adults.
Benign prostatic hyperplasia
The prostate gets larger in most men as they get older. For a symptom-free man of 46 years, the risk of developing BPH over the next 30 years is 45%. Incidence rates increase from 3 cases per 1000 man-years at age 45–49 years, to 38 cases per 1000 man-years by the age of 75–79 years. While the prevalence rate is 2.7% for men aged 45–49, it increases to 24% by the age of 80 years.
Specific phobia
Specific phobias have a one-year prevalence of 8.7% in the USA with 21.9% of the cases being severe, 30.0% moderate and 48.1% mild. The usual age of onset is childhood to adolescence. Women are twice as likely to suffer from specific phobias than men.
Uncombable hair syndrome
Uncombable hair syndrome, also known as Pili trianguli et canaliculi, Spun-glass hair, Struwwelpeter syndrome (see Struwwelpeter) and Cheveux incoiffables, is a rare structural anomaly of the hair with a variable degree of effect. It was first reported in the early 20th century. It typically becomes apparent between the ages of 3 months and 12 years.
Incontinence underwear
It is estimated that 1 in 4 women over the age of 35 experience some level of urinary incontinence, often following childbirth or during menopause. Incontinence is also experienced by approximately 1 in 10 men, commonly related to prostate issues. Incontinence is more prevalent with age, and is commonly experienced by those 65 and over. Due to increased life expectancy and decreased fertility rates, the world population is experiencing a "global greying", which has contributed to an increase in the global market for incontinence products as there is an increasing proportion of people aged over 65.
Facial hair
Facial hair is hair grown on the face, usually on the chin, cheeks, and upper lip region. It is typically a secondary sex characteristic of human males. Men typically start developing facial hair in the later years of puberty or adolescence, between seventeen and twenty years of age, and most do not finish developing a full adult beard until their early twenties or later. This varies, as boys may first develop facial hair between fourteen and sixteen years of age, and boys as young as eleven have been known to develop facial hair. Women are also capable of developing facial hair, especially after menopause, though typically significantly less than men. Men may style their facial hair into beards, moustaches, goatees or sideburns; others completely shave their facial hair. The term "whiskers", when used to refer to human facial hair, indicates the hair on the chin and cheeks.
Late bloomer
During adolescence a child goes through physical and mental changes that lead to them becoming an adult. Adolescence is usually considered to start with the first stages of puberty and to continue until physical growth is complete, although the World Health Organization defines adolescence simply as the period between ages 10 and 20. There is a wide range of normal ages, but generally girls begin the process of puberty between the ages of 9 to 14, reaching adult height and reproductive maturity within 4 years, while boys usually start between the ages of 10 to 17, and continue to grow for about 6 years after the first visible pubertal changes. Adolescence is often a period of turbulent emotions and mood swings combined with rapid, intellectual development.
Pattern hair loss
Because it increases testosterone levels, many Internet forums have put forward the idea that weight training and other forms of exercise increase hair loss in predisposed individuals. Although scientific studies do support a correlation between exercise and testosterone, no direct study has found a link between exercise and baldness. However, a few have found a relationship between a sedentary life and baldness, suggesting some exercise is beneficial. The type or quantity of exercise may influence hair loss.
Testosterone levels are not a good marker of baldness, and many studies actually show paradoxical low testosterone in balding persons, although research on the implications is limited.
Idiopathic generalized epilepsy
This form of epilepsy is very rare, representing less than 1% of cases, and is twice as prevalent in boys compared to girls. Age of seizure onset is between 5 months and 5 years of age. Children with this disorder often present with head drops and brief arm jerks. Although there is believed to be a genetic basis for this disorder, no genetic linkage has been shown.
Depression in childhood and adolescence
In childhood, boys and girls appear to be at equal risk for depressive disorders; during adolescence, however, girls are twice as likely as boys to develop depression. Before adolescence rates of depression are about the same in girls and boys, it is not until between the ages of 11-13 that is begins to change. Young girls around this age, physically, go through more changes than young boys which put that a higher risk for depression and hormonal imbalance. The gender gap in depression between adolescent men and women is mostly due to young women's lower levels of positive thinking, need for approval, and self-focusing negative conditions. Frequent exposure to victimization or bullying was related to high risks of depression, ideation and suicide attempts compare to those not involved in bullying. Nicotine dependence is also associated with depression, anxiety, and poor dieting, mostly in young men. Although causal direction has not been established, involvement in any sex or drug use is cause for concern. Children who develop major depression are more likely to have a family history of the disorder (often a parent who experienced depression at an early age) than patients with adolescent- or adult-onset depression. Adolescents with depression are also likely to have a family history of depression, though the correlation is not as high as it is for children.
Reversible cerebral vasoconstriction syndrome
The average age of onset is 42, but RCVS has been observed in patients aged from 19 months to 70 years. Children are rarely affected. It is more common in females, with a female-to-male ratio of 2.4:1.
Puberty
The first menstrual bleeding is referred to as menarche, and typically occurs about two years after thelarche. The average age of menarche is 12.5 in the United States. Most American girls experience their first period at 11, 12 or 13, but some experience it earlier than their 11th birthday and others after their 14th birthday. In fact, anytime between 8 and 16 is normal. In Canada, the average age of menarche is 12.72, and in the United Kingdom it is 12.9. The time between menstrual periods (menses) is not always regular in the first two years after menarche. Ovulation is necessary for fertility, but may or may not accompany the earliest menses. In postmenarchal girls, about 80% of the cycles were anovulatory in the first year after menarche, 50% in the third year and 10% in the sixth year. Initiation of ovulation after menarche is not inevitable. A high proportion of girls with continued irregularity in the menstrual cycle several years from menarche will continue to have prolonged irregularity and anovulation, and are at higher risk for reduced fertility.
Parkinson's disease
PD is the second most common neurodegenerative disorder after Alzheimer's disease and affects approximately seven million people globally and one million people in the United States. The proportion in a population at a given time is about 0.3% in industrialized countries. PD is more common in the elderly and rates rise from 1% in those over 60 years of age to 4% of the population over 80. The mean age of onset is around 60 years, although 5–10% of cases, classified as young onset PD, begin between the ages of 20 and 50. Males are more often affected than females at a ratio of around 3:2. PD may be less prevalent in those of African and Asian ancestry, although this finding is disputed. Some studies have proposed that it is more common in men than women, but others failed to detect any differences between the two sexes. The number of new cases per year of PD is between 8 and 18 per 100,000 person–years.
Amenorrhea
Primary amenorrhoea can be diagnosed in female children by age 14 if no secondary sex characteristics, such as enlarged breasts and body hair, are present. In the absence of secondary sex characteristics, the most common cause of amenorrhoea is low levels of FSH and LH caused by a delay in puberty. Gonadal dysgenesis, often associated with Turner's Syndrome, or premature ovarian failure may also be to blame. If secondary sex characteristics are present, but menstruation is not, primary amenorrhoea can be diagnosed by age 16. A reason for this occurrence may be that a person phenotypically female but genetically male, a situation known as androgen insensitivity syndrome. If undescended testes are present, they are often removed after puberty (~21 years of age) due to the increased risk of testicular cancer. In the absence of undescended testes, an MRI can be used to determine whether or not a uterus is present. Müllerian agenesis causes around 15% of primary amenorrhoea cases. If a uterus is present, outflow track obstruction may be to blame for primary amenorrhoea.
Myelodysplastic syndrome
The typical age at diagnosis of MDS is between 60 and 75 years; a few people are younger than 50, and diagnoses are rare in children. Males are slightly more commonly affected than females.
Oral pigmentation
Oral pigmentation affects about 3% of the population and is most likely seen in those with dark skin; however people with light skin have, on average, 30 local pigmented areas and in some circumstances will present intra-orally. They are more often found in females than males and the typical age at presentation is 40 years although they can appear at any age.
Urinary incontinence
While urinary incontinence affects older men more often than younger men, the onset of incontinence can happen at any age. Estimates in the mid-2000s suggested that 17 percent of men over age 60, an estimated 600,000 men, experienced urinary incontinence, with this percentage increasing with age.
Osgood–Schlatter disease
Osgood–Schlatter disease generally occurs in boys and girls aged 9–16 coinciding with periods of growth spurts. It occurs more frequently in boys than in girls, with reports of a male-to-female ratio ranging from 3:1 to as high as 7:1. It has been suggested that difference is related to a greater participation by boys in sports and risk activities than by girls.
Gonadotropin-releasing hormone receptor
Normal puberty begins between ages 8 and 14 in girls and between 9 and 14 in boys. Puberty, however, for some children can come much sooner or much later or in many cases never occurs and thereby contributes to the estimated 35-70 million infertile couples worldwide. Among children, the abnormally early or late onset of puberty exerts intense emotional and social stress that too often goes untreated.
Fatal insomnia
The age of onset is variable, ranging from 18 to 60 years, with an average of 50. The disease can be detected prior to onset by genetic testing. Death usually occurs between 7–36 months from onset. The presentation of the disease varies considerably from person to person, even among patients from within the same family.
The disease has four stages:
Other symptoms include profuse sweating, pinpoint pupils, the sudden entrance into menopause for women and impotence for men, neck stiffness, and elevation of blood pressure and heart rate. Constipation is common as well. As the disease progresses, the patient becomes stuck in a state of pre-sleep limbo, or hypnagogia, which is the state just before sleep in healthy individuals. During these stages, patients commonly repeatedly move their limbs as if dreaming.
2000s in fashion
For European men aged 25–40, shorter hair styles that usually took the form of a quiff were fashionable in the early 2000s, as well as spiked hair and fauxhawks for men aged 18–30. Dark-haired young British men often had dyed-blonde weaves and streaks until the late 2000s when a natural hair color became the norm again. A common haircut among American men and boys was the frosted spiky hair popularized by boybands and pop punk bands from 1996 through 2004. Meanwhile, the crew cut and buzzcut remained popular among balding American and Middle Eastern men from the mid 1990s until the 2010s.
Hair loss
The psychology of hair thinning is a complex issue. Hair is considered an essential part of overall identity: especially for women, for whom it often represents femininity and attractiveness. Men typically associate a full head of hair with youth and vigor. Although they may be aware of pattern baldness in their family, many are uncomfortable talking about the issue. Hair thinning is therefore a sensitive issue for both sexes. For sufferers, it can represent a loss of control and feelings of isolation. People experiencing hair thinning often find themselves in a situation where their physical appearance is at odds with their own self-image and commonly worry that they appear older than they are or less attractive to others. Psychological problems due to baldness, if present, are typically most severe at the onset of symptoms.
MORM syndrome
For individuals with MORM syndrome, symptoms do not appear until about one year into the child’s life span. From conception to birth, individuals with MORM syndrome appear asymptotic with no abnormal characteristics. Vision is negatively affected within the first year of life, particularly night vision. Individuals with MORM syndrome experience decreased visual acuity meaning their ability to see distinct sharp lines decreases. Vision quality continues to deteriorate until age three. Any further reduction in vision acuity is not observed until the individual is between the ages thirty to forty. Delayed sentence processing and intellectual disability is associated with individuals with MORM syndrome, primarily observed at age four. Individuals continue to develop and grow until they are five to twelve years old. During this age bracket, truncal obesity can develop. Truncal obesity is a term used to describe the build up of fat around one's trunk or torso as opposed to the persons extremities. Males enter puberty at around age twelve and develop normally except for their sex organ. The male's penis will remain at the prepubescent size resulting in a micropenis. The life span of individuals with MORM syndrome is unclear as well as the fertility of these individuals.
Cluster headache
Cluster headache affects about 0.1% of the general population at some point in their life. Males are affected about four times more often than females. The condition usually starts between the ages of 20 and 50 years, although it can occur at any age. About one in five of adults reports the onset of cluster headache between 10 and 19 years.
Pattern hair loss
Many myths are given regarding the possible causes of baldness and its relationship with one's virility, intelligence, ethnicity, job, social class, wealth, etc.
Prostate cancer
A complete understanding of the causes of prostate cancer remains elusive. The primary risk factors are obesity, age, and family history. Prostate cancer is very uncommon in men younger than 45, but becomes more common with advancing age. The average age at the time of diagnosis is 70. Many men never know they have prostate cancer. Autopsy studies of Chinese, German, Israeli, Jamaican, Swedish, and Ugandan men who died of other causes have found prostate cancer in 30% of men in their fifties, and in 80% of men in their seventies. Men who have first-degree family members with prostate cancer appear to have double the risk of getting the disease compared to men without prostate cancer in the family. This risk appears to be greater for men with an affected brother than for men with an affected father. In the United States in 2005, there were an estimated 230,000 new cases of prostate cancer and 30,000 deaths due to prostate cancer. Men with high blood pressure are more likely to develop prostate cancer. There is a small increased risk of prostate cancer associated with lack of exercise.
Schizophrenia
Late adolescence and early adulthood are peak periods for the onset of schizophrenia, critical years in a young adult's social and vocational development. In 40% of men and 23% of women diagnosed with schizophrenia, the condition manifested itself before the age of 19. The most general symptoms of schizophrenia tend to appear between ages 16 and 30. The onset of the disorder is usually between ages 18 and 25 for men and between 25 and 35 for women. To minimize the developmental disruption associated with schizophrenia, much work has recently been done to identify and treat the prodromal (pre-onset) phase of the disorder, which has been detected up to 30 months before the onset of symptoms. Those who go on to develop schizophrenia may experience transient or self-limiting psychotic symptoms and the non-specific symptoms of social withdrawal, irritability, dysphoria, and clumsiness before the onset of the disease. Children who go on to develop schizophrenia may also demonstrate decreased intelligence, decreased motor development (reaching milestones such as walking slowly), isolated play preference, social anxiety, and poor school performance.
Cerebellar degeneration
Cerebellar degeneration continues to carry a considerable burden on the health of the world population, as well as on health agencies and governing bodies across the globe. Cerebellum-related disorders generally transpire in individuals between the ages of 45 to 65 years, however the age of symptomatic onset differs in accordance with the underlying cause of the degenerative disorder. For paraneoplastic cerebellar degeneration, the average age of onset is 50 years, generally affecting a greater population of males than females. Nutritional and alcoholic cerebellar degeneration, being more prevalent than paraneoplastic cerebellar degeneration, affects individuals with a thiamine deficiency and dipsomaniacs, respectively. Recent epidemiological studies on cerebellar degeneration estimated a global prevalence rate of 26 per 100,000 cases of cerebellar degeneration in children.
Pregnancy over age 50
Men also experience a decline in fertility as they age though in a very gradual and later process in contrast to women's fertility as men's biological clock declines simply by each age (loses 1 percent every age) in comparison to women's biological clock where it begins drop sharply and rapidly after 38 years of age; for example, the average time to pregnancy if a man is under 25 is just over 4.5 months but nearly two years if a man is over 40 (if the woman is under 25). The risk of genetic defects is greatly increased due to the paternal age effect. Children with fathers aged 40 or older are more than five times as likely to have an autism spectrum disorder than children fathered by men aged under 30. Researchers estimate that compared to a male fathering a child in his early 20s, there is double the chance of the child getting schizophrenia when the father is age 40, and triple the risk of schizophrenia when the father is age 50 (though, for most people this means the risk goes from approximately 1 in 121 when a man is 29, to 1 in 47 when a man is age 50 to 54). Men's fertility declines throughout the lifespan, with the volume and fecundity of a man’s semen quality and sperm motility (the ability of sperm to move towards an egg) decrease continually between the ages of 20 and 80. The incidence of dwarfism and miscarriage also increases as men age
Eales disease
Eales disease most commonly affects healthy young adults. Male predominance (up to 97.6%) has been reported in a majority of the series. The predominant age of onset of symptoms is between 20 and 30 years. The disease is now seen more commonly in the Indian subcontinent.
Eagle syndrome
Patients with this syndrome tend to be between 30 and 50 years of age but it has been recorded in teenagers and in patients > 75 years old. It is more common in women, with a male:female ratio ~ 1:2.
Hair care
There are various reasons for hair loss, most commonly hormonal issues. Fluctuations in hormones will often show in the hair. Not all hair loss is related to what is known as male pattern baldness, women can suffer from baldness just as men do. Formulas for addressing this specific cause of lack of hair growth yet typically they require around three months of consistent use for results to begin to appear. Cessation may also mean that gained growth may dissipate.
Fertility and intelligence
In 1982, Daniel R. Vining, Jr. sought to address these issues in a large study on the fertility of over 10,000 individuals throughout the United States, who were then aged 25 to 34. The average fertility in his study was correlated at −0.86 with IQ for white women and −0.96 for black women. Vining argued that this indicated a drop in the genotypic average IQ of 1.6 points per generation for the white population, and 2.4 points per generation for the black population.
In considering these results along with those from earlier researchers, Vining wrote that "in periods of rising birth rates, persons with higher intelligence tend to have fertility equal to, if not exceeding, that of the population as a whole," but, "The recent decline in fertility thus seems to have restored the dysgenic trend observed for a comparable period of falling fertility between 1850 and 1940." To address the concern that the fertility of this sample could not be considered complete, Vining carried out a follow-up study for the same sample 18 years later, reporting the same, though slightly decreased, negative correlation between IQ and fertility.
Lupus erythematosus
Lupus can develop in any age but most commonly in ages 15 to 44 with varying results. Typically, the manifestation of the disease tends to be more acute in those affected who are of younger age. Women are more likely to get it than men. Patients with juvenile onset Lupus in particular, are vulnerable to mucocutaneous manifestations of the disease (alopecia, skin rash, and ulceration of the mucus membranes) more so than any other age group. However, patients with late onset Lupus have a much higher mortality rate. Nearly 50% of those with late onset Lupus die of their affliction. Women who are of childbearing age are also particularly at risk.
Prostate cancer
Although the widespread use of prostate-specific antigen (PSA) screening in the US has resulted in diagnosis at earlier age and cancer stage, the vast majority of cases are still diagnosed in men older than 65 years, and approximately 25% of cases are diagnosed in men older than 75 years. Though US National Comprehensive Cancer Network guidelines recommend using life expectancy greater than or less than 10 years to help make treatment decisions, in practice, many elderly patients are not offered curative treatment options such as radical prostatectomy or radiation therapy and are instead treated with hormonal therapy or watchful waiting. This pattern can be attributed to factors such as medical co-morbidity and patient preferences is regard to quality of life in addition to prostate cancer specific risk factors such as pretreatment PSA, Gleason score and clinical stage. As the average life expectancy increases due to advances in the treatment of cardiovascular, pulmonary and other chronic diseases, it is likely that more elderly patients will be living long enough to suffer the consequences of their prostate cancer. Therefore, there is currently much interest in the role of aggressive prostate cancer treatment modalities such as with surgery or radiation in the elderly population who have localized disease.
Puberty
One possible cause of a delay in the onset of puberty past the age 14 in girls and 15 in boys is Kallmann syndrome, a form of hypogonadotropic hypogonadism (HH). Kallmann syndrome is also associated with a lack of sense of smell (anosmia). Kallmann syndrome and other forms of HH affect both men and women. It is caused by a failure in HPG axis at puberty which results in low or zero gonadotropin (LH and FSH) levels with the subsequent result of a failure to commence or complete puberty, secondary hypogonadism and infertility.
Diagnosis of multiple sclerosis
The primary progressive subtype occurs in approximately 10–20% of individuals, with no remission after the initial symptoms. It is characterized by progression of disability from onset, with no, or only occasional and minor, remissions and improvements. The usual age of onset for the primary progressive subtype is later than of the relapsing-remitting subtype. It is similar to the age that secondary progressive usually begins in relapsing-remitting MS, around 40 years of age.
Social anxiety disorder
The mean onset of social phobia is 10 to 13 years. Onset after age 25 is rare and is typically preceded by panic disorder or major depression. Social anxiety disorder occurs more often in females than males. The prevalence of social phobia appears to be increasing among white, married, and well-educated individuals. As a group, those with generalized social phobia are less likely to graduate from high school and are more likely to rely on government financial assistance or have poverty-level salaries. Surveys carried out in 2002 show the youth of England, Scotland, and Wales have a prevalence rate of 0.4 percent, 1.8 percent, and 0.6 percent, respectively. In Canada, the prevalence of self-reported social anxiety for Nova Scotians older than 14 years was 4.2 percent in June 2004 with women (4.6 percent) reporting more than men (3.8 percent). In Australia, social phobia is the 8th and 5th leading disease or illness for males and females between 15–24 years of age as of 2003. Because of the difficulty in separating social phobia from poor social skills or shyness, some studies have a large range of prevalence. The table also shows higher prevalence in Sweden.
Duchenne muscular dystrophy
Duchenne muscular dystrophy (DMD) is a severe type of muscular dystrophy. The symptom of muscle weakness usually begins around the age of four in boys and worsens quickly. Typically muscle loss occurs first in the upper legs and pelvis followed by those of the upper arms. This can result in trouble standing up. Most are unable to walk by the age of 12. Affected muscles may look larger due to increased fat content. Scoliosis is also common. Some may have intellectual disability. Females with a single copy of the defective gene may show mild symptoms.
The disorder is X-linked recessive. About two thirds of cases are inherited from a person's mother, while one third of cases are due to a new mutation. It is caused by a mutation in the gene for the protein dystrophin. Dystrophin is important to maintain the muscle fiber's cell membrane. Genetic testing can often make the diagnosis at birth. Those affected also have a high level of creatine kinase in their blood.
Although there is no known cure, physical therapy, braces, and corrective surgery may help with some symptoms. Assisted ventilation may be required in those with weakness of breathing muscles. Medications used include steroids to slow muscle degeneration, anticonvulsants to control seizures and some muscle activity, and immunosuppressants to delay damage to dying muscle cells.
DMD affects about one in 5,000 males at birth. It is the most common type of muscular dystrophy. The average life expectancy is 26; however, with excellent care, some may live into their 30s or 40s. Gene therapy, as a treatment, is in the early stages of study in humans.
X-linked dystonia parkinsonism
Although all early reported cases occurred in the Philippines, X-linked dystonia parkinsonism has been diagnosed in the US, Canada, and Germany in people of Filipino descent. The prevalence in the Philippines has been estimated at 1/322,000 and as high as 1/4,000 in the province of Capiz's male population. As x-linked recessive disease, the majority of those affected are males with females generally asymptomatic carriers. In the largest described series, the mean age of onset was 39.7 years, the mean duration of illness was 16 years, and the mean age of death was 55.6 years.
Xanthelasma
Xanthelasma is a rare disorder in the general population, with a variable incidence of 0.56%–1.5% in western developed countries. The age of onset ranges from 15 to 75 with a peak in the 4th to 5th decades of life. There also seems to be a greater prevalance in females, but this might be due to higher consciousness to cosmetic defects.
Brent Guerra
Guerra experienced male pattern balding at a young age and made headlines in late 2005 when he underwent a hair transplant cosmetic surgery procedure. He has said that the operation gave him confidence both on and off the field.
Prostaglandin-D synthase
In March 2012 American scientists reported a discovery that shows this enzyme triggers male baldness According to the discovery, levels of this enzyme are elevated in the cells of hair follicles located in bald patches on the scalp, but not in hairy areas. The research could lead to a cream to treat baldness.
Acrocallosal syndrome
Acrocallosal syndrome (ACLS, ACS, Schinzel-Type, Hallux-duplication) is a rare, heterogeneous [3] autosomal recessive disorder first discovered by Albert Schinzel (1979) in a 3-year-old boy . To inherit ACLS, one gene copy from each parent must contain a mutation somewhere in the KIF7 gene and be passed on to the child [3]. Characteristics of this syndrome include absence or poor development of the area connecting the left and right parts of the brain, an abnormally large head, increased distance between facial features (eyes), poor motor skills, mental retardation [2], extra fingers and toes, many facial deformities [3], and cleft palate [5]. This is considered a rare disorder and is placed on the NIH Office of Rare Diseases (fewer than 200,000 cases) rare disease list [8]. Lifespan may range from stillbirth to normal expectancy depending on pregnancy complications and severity of the disorder [2,3,5]. In mild cases, the subjects have been shown to live relatively normal lives, but with developmental delays [2].
Epidemiology of schizophrenia
Schizophrenia is diagnosed 1.4 times more frequently in males than females, and typically appears earlier in men—the peak ages of onset are 20–28 years for males and 26–32 years for females. Onset in childhood is much rarer, as is onset in middle- or old age.
Generalized anxiety disorder
5.9 percent of adults were affected by GAD in 2019.The usual age of onset is variable, from childhood to late adulthood, with the median age of onset being approximately 31 and mean age of onset is 32.7. Most studies find that GAD is associated with an earlier and more gradual onset than the other anxiety disorders. The prevalence of GAD in children is approximately 3%; the prevalence in adolescents is reported as high as 10.8%. When GAD appears in children and adolescents, it typically begins around 8 to 9 years of age.
Toilet training
In 2002, the average age that parents recognized their child "showing an interest in using the potty" was 24–25 months, and daytime dryness was achieved on average at almost 3 years of age. Now nighttime accidents are considered normal until 5 or 6 years of age.
Pattern hair loss
Although baldness is not as common in women as in men, the psychological effects of hair loss tend to be much greater. Typically, the frontal hairline is preserved, but the density of hair is decreased on all areas of the scalp. Previously, it was believed to be caused by testosterone just as in male baldness, but most women who lose hair have normal testosterone levels.
Effects of estrogen on schizophrenia
Gender differences have been observed in the age of onset of schizophrenia. Women have a later age of onset and on average they are diagnosed 2 to 10 years later than men. In fact, the first onset of schizophrenia for men occurs around the ages of 20 to 25, while in women the first onset generally occurs between the ages of 25 to 30 years. However, it has also been noted that in women a second peak in schizophrenia occurs at the ages of 40 to 45. During this period there is a significant drop in estrogen levels in the body. These factors have led researchers to believe that estrogen may have an effect on psychosis in women.
Thymoma
Men and women are equally affected by thymomas. The typical age at diagnosis is 30–40, although cases have been described in every age group, including children.
Canine follicular dysplasia
Color dilution alopecia is an inherited type of follicular dysplasia. It most commonly affects dogs with blue or fawn coats, which are dilutions of black and brown, respectively. Dilution is caused by irregularities in melanin transfer and storage. Melanosomes may clump within melanocytes of the skin and hair follicles, causing the hair shafts to easily fracture. Signs of color dilution alopecia include hair loss and recurrent skin infection on the back. It can involve the whole body. The condition starts between the ages of six months and two years, depending on the degree of dilution. Early hair loss occurs due to hair breakage, making it similar to structural follicular alopecia. It is important to treat the skin infections, and etretinate has been used to treat the hair loss.The Siberian Husky and Alaskan Malamute have a type of follicular dysplasia that occurs between the ages of three and four months, possibly later in the Malamute. The guard hairs of the trunk are progressively lost and the coat turns reddish in color.
Familial male-limited precocious puberty
Familial male-limited precocious puberty, often abbreviated as FMPP, also known as familial sexual precocity or gonadotropin-independent testotoxicosis, is a form of gonadotropin-independent precocious puberty in which boys experience early onset and progression of puberty. Signs of puberty can develop as early as an age of 1 year.
Hair loss
Hair loss, also known as alopecia or baldness, refers to a loss of hair from part of the head or body. Typically at least the head is involved. The severity of hair loss can vary from a small area to the entire body. Typically inflammation or scarring is not present. Hair loss in some people causes psychological distress.
Common types include: male-pattern hair loss, female-pattern hair loss, alopecia areata, and a thinning of hair known as telogen effluvium. The cause of male-pattern hair loss is a combination of genetics and male hormones, the cause of female pattern hair loss is unclear, the cause of alopecia areata is autoimmune, and the cause of telogen effluvium is typically a physically or psychologically stressful event. Telogen effluvium is very common following pregnancy.
Less common causes of hair loss without inflammation or scarring include the pulling out of hair, certain medications including chemotherapy, HIV/AIDS, hypothyroidism, and malnutrition including iron deficiency. Causes of hair loss that occurs with scarring or inflammation include fungal infection, lupus erythematosus, radiation therapy, and sarcoidosis. Diagnosis of hair loss is partly based on the areas affected.
Treatment of pattern hair loss may simply involve accepting the condition. Interventions that can be tried include the medications minoxidil (or finasteride) and hair transplant surgery. Alopecia areata may be treated by steroid injections in the affected area, but these need to be frequently repeated to be effective. Hair loss is a common problem. Pattern hair loss by age 50 affects about half of males and a quarter of females. About 2% of people develop alopecia areata at some point in time.
Baldness is the partial or complete lack of hair growth, and part of the wider topic of "hair thinning". The degree and pattern of baldness varies, but its most common cause is androgenic hair loss, "alopecia androgenetica", or "alopecia seborrheica", with the last term primarily used in Europe.
Enuresis
Techniques that may help daytime incontinence include:In the United States, approximately 15 to 20 percent of 5-year-old children will develop symptoms related to this disorder. Prevalence changes significantly with age. To be more specific, about 33 percent of 5 year-olds, 25 percent of 7 year olds, 15 percent of 9 year olds, 8 percent of 11 year olds, 4 percent of 13 year-olds, and 3 percent of 15 to 17 year-olds. Numbers show that diurnal enuresis is much less common. Overall, about 60 percent of those suffering are male. However, this too depends on age. From ages 4 to 6, the number of boys and girls is about equal. However, the ratio changes so that by 11 years of age there are twice as many boys as girls. Incidence varies with social class with more incidences among those with low socioeconomic status. No evidence has been found related to ethnic differences. Approximately 85% of children with enuresis have primary enuresis because they have never maintained consistent bedwetting behaviors for at least 6 months.
Menarche
Girls experience menarche at different ages. The timing of menarche is influenced by female biology, as well as genetic and environmental factors, especially nutritional factors. The mean age of menarche has declined over the last century, but the magnitude of the decline and the factors responsible remain subjects of contention. The worldwide average age of menarche is very difficult to estimate accurately, and it varies significantly by geographical region, race, ethnicity and other characteristics. Various estimates have placed it at 13. Some estimates suggest that the "median" age of menarche worldwide is 14, and that there is a later age of onset in Asian populations compared to the West. The average age of menarche is about 12.5 years in the United States, 12.72 in Canada, and 12.9 in the UK. A study of girls in Istanbul, Turkey, found the median age at menarche to be 12.74 years.
Hamilton–Norwood scale
The progression of male pattern baldness is generally classified on the Hamilton–Norwood scale, which ranges from stages I to VII.
Kidney stone disease
The total cost for treating urolithiasis was US$2 billion in 2003. About 65–80% of those with kidney stones are men; most stones in women are due to either metabolic defects (such as cystinuria) or infection. (p. 1057) Men most commonly experience their first episode between 30 and 40 years of age, whereas for women, the age at first presentation is somewhat later. The age of onset shows a bimodal distribution in women, with episodes peaking at 35 and 55 years. Recurrence rates are estimated at 50% over a 10-year and 75% over 20-year period, with some people experiencing ten or more episodes over the course of a lifetime.
LPAR6
In February 2008 researchers at the University of Bonn announced they have found the genetic basis of two distinct forms of inherited hair loss, opening a broad path to treatments for baldness. They found that mutations in the gene P2RY5 causes a rare, inherited form of hair loss called Hypotrichosis simplex. It is the first receptor in humans known to play a role in hair growth. The fact that any receptor plays a specific role in hair growth was previously unknown to scientists and with this new knowledge a focus on finding more of these genes may be able to lead to therapies for many different types of hair loss.
Moustache
The moustache and other forms of facial hair are globally understood to be signs of the post-pubescent male, however those with moustaches are perceived to be older than those who are clean-shaven of the same age. This was determined by manipulating a photo of six male subjects, with varying levels of baldness, to have moustaches and beards and then asking undergraduate college students to rate both the photos of the men with facial hair and without facial hair in terms of social maturity, aggression, age, appeasement, and attractiveness. Regardless of how bald the subject was, the results found in relation to the perception of moustaches remained constant. Although males with facial hair were perceived, in general, to be older than the same subject pictured without facial hair, the moustached subjects were also perceived to be far less socially mature. The decreased perception of social maturity of the moustached men may partially be due to the increase in the perception of aggression in the moustached men, as aggression is incompatible with social maturity.
Scalp
The scalp is a common site for the development of tumours including:The scalp plays an important role in the aesthetics of the face. Androgenic alopecia, or male pattern hair loss, is a common cause of concern to men. It may be treated with varying rates success by medication (e.g. finasteride, minoxidil) or hair transplantation. If the scalp is heavy and loose, a common change with ageing, the forehead may be low, heavy and deeply lined. The brow lift procedure aims to address these concerns.
Toupée
Other trends leading to the decline in toupée use include a rise in acceptance of baldness by those men afflicted with it. Short haircuts, in fashion since the 1990s, have tended to minimize the appearance of baldness, and many balding men choose to shave their heads entirely.