***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: The salivary enzyme alpha-amylase has been proposed to indicate stress-reactive bodily changes . A previous study by the authors revealed marked increases in salivary alpha-amylase following psychosocial stress , indicating a stress-dependent activation of salivary alpha-amylase . Salivary alpha-amylase has been suggested to reflect catecholaminergic reactivity . Our aim was to assess/evaluate a possible relationship between salivary alpha-amylase and adrenergic parameters , i.e. catecholamines , as well as other stress markers . Using an intra-individual repeated measures design , 30 healthy young men underwent the Trier Social Stress Test ( TSST )  , which consists of a mental arithmetic task and free speech in front of an audience and a control condition in r and omized order .  Salivary alpha-amylase and salivary cortisol as well as plasma catecholamines and cardiovascular activity were repeatedly measured before , during , and after both conditions . Significant differences were found between the stress and the rest condition in salivary alpha-amylase , salivary cortisol , plasma catecholamines , and cardiovascular parameters ( heart rate , LF , HF , LF/HF ) . However , general alpha-amylase responses ( area under the curve ) were not associated with general responses in catecholamines and cortisol in the stress condition ( r smaller than 0.25 for all analyses ) . Analysis of cardiovascular parameters indicates a positive relationship between amylase and sympathetic tone ( LF/HF ) during stress . Salivary alpha-amylase is sensitive to psychosocial stress . Since it does not seem to be closely related to other biological stress markers such as catecholamines and cortisol , salivary alpha-amylase may be a useful additional parameter for the measurement of stress This investigation evaluates the moderating influence of social support on the negative effects of stress for family caregivers and vali date s the Perceived Stress Scale as a st and ard of measurement . Seventy-five family caregivers to older adults with heart failure were interviewed in their homes about  perceived stress  ,  depressive symptoms , and social support after hospital discharge . The Perceived Stress Scale demonstrated internal consistency . Social support did not moderate the effects of stress on depressive symptoms . Lack of a significant association between salivary cortisol and the Perceived Stress Scale did not support testing of construct validity . Stress levels , however , frequently vary due to caregiving dem and s and additional influencing factors Background Psychosocial stress is a risk factor for coronary heart disease ( CHD ) . The mechanisms are incompletely understood , although dysfunction of the hypothalamic pituitary adrenal ( HPA ) axis might be involved . We examined the association between cortisol responses to laboratory-induced mental stress and the progression of coronary artery calcification ( CAC ) . Methods and Results Participants were 466 healthy men and women ( mean age = 62.7±5.6 yrs ) , without history or objective signs of CHD , drawn from the Whitehall II epidemiological cohort . At the baseline assessment  salivary cortisol  was measured in response to mental stressors , consisting of a 5-min Stroop task and a 5-min mirror tracing task . CAC was measured at baseline and at 3 years follow up using electron beam computed tomography . CAC progression was defined as an increase > 10 Agatston units between baseline and follow up . 38.2 % of the sample demonstrated CAC progression over the 3 years follow up . There was considerable variation in the cortisol stress response , with approximately 40 % of the sample responding to the stress tasks with an increase in cortisol of at least 1 mmol/l . There was an association between cortisol stress reactivity ( per SD ) and CAC progression ( odds ratio = 1.27 , 95 % CI , 1.02–1.60 ) after adjustments for age , sex , pre-stress cortisol , employment grade , smoking , resting systolic BP , fibrinogen , body mass index , and use of statins . There was no association between systolic blood pressure reactivity and CAC progression ( odds ratio per SD increase = 1.03 , 95 % CI , 0.85–1.24 ) . Other independent predictors of CAC progression included age , male sex , smoking , resting systolic blood pressure , and fibrinogen . Conclusion Results demonstrate an association between heightened cortisol reactivity to stress and CAC progression . These data support the notion that cortisol reactivity , an index of HPA function , is one of the possible mechanisms through which psychosocial stress may influence the risk of CHD Assessment of sympathoadrenal medullary system ( SAM ) activity is only possible to date via measurement of catecholamines in blood plasma or via electrophysiological methods . Both ways of measurement are restricted to endocrinological or psychophysiological laboratories , as both require either immediate freezing of blood sample s or complex recording devices . Efforts have therefore been undertaken to find a method comparable to salivary cortisol measurements , in which noninvasive sample s can be taken at any place and stored at room temperature for sufficient time before later analysis in the laboratory . Salivary alpha-amylase ( sAA ) is a c and i date that may prove useful in this context . We show here that sAA activity is increased by acute psychosocial stress  ( Trier Social Stress Test )  and that increases in sAA correlate with increases in norepinephrine . We further report that sAA exhibits a stable circadian pattern that mirrors that of salivary cortisol . In conclusion , the current data show that salivary alpha-amylase may serve as an easy-to-use index for SAM activity . However , some questions remain to be answered ; for example , what impact does salivary flow rate exert on stress-induced sAA activity This investigation was design ed to evaluate the production rates and concentrations of salivary alpha-amylase as a measure of adrenergic activity under several conditions of stress in human subjects .  Saliva and blood sample s were simultaneously collected from men at four 15 min intervals both before and after regimens for exercise , a written examination , or a rest period . The regressions of salivary alpha-amylase on plasma norepinephrine ( NE ) concentrations were significant for both exercise ( P < 0.001 ) and examination ( P < 0.01 ) protocol s. Aerobic exercise induced a 3-fold mean increase in alpha-amylase ; both NE and epinephrine ( EP ) increased approximately 5-fold over control levels . Levels of alpha-amylase and NE returned to control levels within 30 - 45 min after exercise , but EP remained elevated by approximately 2-fold during the remaining hour of observation . During the written examination , alpha-amylase and NE , but not EP , concentrations increased in parallel . In further studies the effects of exercise and exposure to heat and cold on the relationship of salivary alpha-amylase to heart rate and body temperature were investigated . Greater intensities of exercise were associated with greater increases in alpha-amylase concentrations . During heat exposure in a sauna ( 66 degrees C for 40 min ) amylase , heart rate and body temperature all increased progressively . However , during exposure to cold ( 4 degrees C for 40 min ) amylase increased rapidly , though heart rate and body temperature remained unchanged . Salivary cortisol concentrations were unchanged during exposure to heat or cold . We conclude that salivary alpha-amylase concentrations are predictive of plasma catecholamine levels , particularly NE , under a variety of stressful conditions , and may be a more direct and simple end point of catecholamine activity than are changes in heart rate Chronic stress can result in frequent or persistent challenges of the hypothalamic-pituitary-adrenal ( HPA ) axis result ing in abnormal cortisol patterns and increased risk for cardiovascular disease ( CVD ) . Police work is an environment replete with stress . The present article describes associations between cortisol , a biomarker of stress , and brachial artery flow mediated dilation ( FMD ) in police officers . A r and om sample stratified on gender ( n=100 , 33 % women ) was generated from officers in a mid-sized urban department . Four salivary cortisol parameters were derived : after awakening , following a st and ardized high protein meal challenge , during the entire day , and after a dexamethasone suppression test . Continuous scan B-Mode ultrasound was used to measure percent change in brachial artery FMD following occlusion and release . Elevated cortisol secretion after awakening was significantly associated with  impaired FMD in women , reflected by an inverse trend . Adjustment for age , smoking , and alcohol consumption did not appreciably alter this trend . A similar result was not evident among male officers . Responses of other cortisol challenges to the HPA axis were not associated with FMD . In conclusion , increased cortisol secretion after awakening was independently associated with impaired FMD  in female police officers only , indicating a possible link between HPA axis stress response and sub clinical CVD . However , because associations were not found with other cortisol parameters and were not evident in male officers , replication of these findings with a prospect i ve study design may be warranted OBJECTIVE The pathophysiological pathways from stress caused by psychosocial stress to IHD has not been dealt with very extensively . The objective of this study was to analyse the association between cortisol levels and progression in intima media thickness ( IMT ) . METHODS AND RESULTS In 1998 and 2002 , 95 participants went through a clinical investigation including ultrasound of the artery carotis communis .  Progression in IMT was analysed in relation to levels of salivary cortisol in 1998 and the average levels of salivary cortisol in 1998/2002 . Further , the significance of conventional coronary risk factors , testosterone and dehydro-epi and rosterone sulphate ( DHEAS ) were evaluated . Among the men , only age and HDL-cholesterol ( negative ) were significantly correlated with progression in IMT . Among the women , awakening cortisol response was significantly correlated with progression in IMT . Testosterone and DHEAS were borderline significantly associated ( negatively ) with progression in IMT in both genders . CONCLUSION Progression in atherosclerosis were determined by different risk factors in women and men . The awakening cortisol response was of great importance to IMT progression in women but not in men OBJECTIVES Previous studies have suggested that abnormal levels of cortisol and testosterone might increase the risk of serious somatic diseases . To test this hypothesis , we conducted a 5-year follow-up study in middle-aged men . METHODS A population -based cohort study conducted in 1995 amongst 141 Swedish men born in 1944 , in whom a clinical examination supplemented by medical history aim ed to disclose the presence of cardiovascular disease ( CVD ) ( myocardial infa rct ion , angina pectoris , stroke ) , type 2 diabetes and hypertension were performed at baseline and at follow-up in the year 2000 . In addition ,  salivary cortisol levels  were measured repeatedly over the day .  Serum testosterone concentrations  were also determined . Using the baseline data , an algorithm was constructed , which classified the secretion pattern of cortisol and testosterone from each individual as being normal or abnormal . RESULTS By the end of follow-up , men with an abnormal hormone secretion pattern ( n = 73 ) had elevated mean arterial pressure ( P = 0.003 ) , fasting insulin ( P = 0.009 ) and insulin : glucose ratio ( P = 0.005 ) compared with men with a normal secretion pattern ( n = 68 ) . Body mass index , waist circumference , and waist : hip ratio were significantly elevated in both groups . However , the 5-year incidence of CVD , type 2 diabetes , and hypertension were significantly higher ( P < 0.001 ) in men with an abnormal neuroendocrine secretory pattern compared to men with a normal pattern . CONCLUSIONS These data suggest that an abnormal neuroendocrine secretory pattern is prospect ively associated with an increased incidence of cardiovascular-related events and type 2 diabetes Hyperactivity of the hypothalamic-pituitary-adrenal axis ( HPAA ) result ing from fetal programming may play a role in the development of high blood pressure ( BP ) in black people . We assessed the  diurnal salivary cortisol profile  in children with and without increased BP and evaluated their mother 's HPAA . In a cross-sectional study , 20 Afro-Caribbean children ( mean age 9.6 years ) with higher blood pressures and 20 children with lower blood pressures were chosen from a prospect i ve study of 569 mothers and children in Jamaica .  Daytime salivary cortisol profiles  were collected in the children and their mothers . The mothers were also assessed for features of the metabolic syndrome .  Children with higher BP had higher mean morning salivary cortisol concentrations than those with lower BP ( 7.9 S.D. 1.9 vs. 4.5 S.D. 2.4nmol/l ; p=0.03 ) . Their mothers also had increased morning salivary cortisol concentrations ( 9.9 S.D. 1.8 vs. 5.5 S.D. 2.5nmol/l ; p=0.02 ) , but no changes in fasting glucose , insulin , lipids , BP or adiposity . Maternal and offspring cortisol concentrations correlated significantly ( r=0.465 , p=0.004 ) . Maternal cortisol concentrations were significantly associated with the child 's BP . We conclude that Afro-Caribbean children with higher BP have higher morning salivary cortisol concentrations . The children 's cortisol concentrations correlate significantly with the mother 's cortisol concentrations . These findings suggest that the HPAA 
    Output:
    
Results : Cortisol was the biomarker used most frequently .
Overall , psychosocial stress was associated with CVD risks such as vascular pathology ( hypertension , blood pressure fluctuation , and carotid artery plaque ) as well as metabolic factors such as abnormal blood glucose , dyslipidemia , and elevated cardiac enzymes .
Conclusion : Diverse salivary biomarkers have been useful in stress research , particularly when linked to CVD risks