Obstructive sleep apnea hypopnea is a very common disorder, affecting at least 1%—2% of children, 2%—15% of middle-age adults, and more than 20% of older individuals. In the general community, prevalence rates of undiagnosed obstructive sleep apnea hypopnea may be very high in elderly individuals. Since the disorder is strongly associated with obe- sity, increases in obesity rates are likely to be accompanied by an increased prevalence of this disorder. Prevalence may be particularly high among males, older adults, and certain racial/ethnic groups. In adults, the male-to—female ratio of obstructive sleep apnea hypop- nea ranges from 2:1 to 4:1. Gender differences decline in older age, possibly because of an increased prevalence in females after menopause. There is no gender difference among prepubertal children.
The age distribution of obstructive sleep apnea hypopnea likely follows a J-shaped distri- bution. There is a peak in children ages 3—8 years when the nasopharynx may be compro- mised by a relatively large mass of tonsillar tissue compared with the size of the upper airway. With growth of the airway and regression of lymphoid tissue during later child- hood, there is reduction in prevalence. Then, as obesity prevalence increases in midlife and females enter menopause, obstructive sleep apnea hypopnea again increases. The course in older age is unclear; the disorder may level off after age 65 years, but in other individ- uals, prevalence may increase with aging. Because there is some age dependency of the oc- currence of apneas and hypopneas, polysomnographic results must be interpreted in light of other clinical data. In particular, significant clinical symptoms of insomnia or hyper- somnia should be investigated regardless of the individual’s age.
Obstructive sleep apnea hypopnea usually has an insidious onset, gradual progression, and persistent course. Typically the loud snoring has been present for many years, often since childhood, but an increase in its severity may lead the individual to seek evaluation. Weight gain may precipitate an increase in symptoms. Although obstructive sleep apnea hypopnea can occur at any age, it most commonly manifests among individuals ages 40—60 years. Over 4—5 years, the average apnea hypopnea index increases in adults and older individuals by ap— proximately two apneas/hypopneas per hour. The apnea hypopnea index is increased and in- cident obstructive sleep apnea hypopnea is greater among individuals who are older, who are male, or who have a higher baseline body mass index (BMI) or increase their BMI over time.
Spontaneous resolution of obstructive sleep apnea hypopnea has been reported with weight loss, particularly after bariatric surgery. In children, seasonal variation in obstructive sleep ap- nea hypopnea has been observed, as has improvement with overall growth.