Mortality related to actigraphic long and short sleep.

BACKGROUND: The folk belief that we should sleep 8 h seems to be incorrect. Numerous studies have shown that self-reported sleep longer than 7.5 h or shorter than 6.5 h predicts increased mortality risk. This study examined if prospectively-determined objective sleep duration, as estimated by wrist actigraphy, was associated with mortality risks. METHODS: From 1995-1999, women averaging 67.6 years of age provided one-week actigraphic recordings. Survival could be estimated from follow-up continuing until 2009 for 444 of the women, with an average of 10.5 years before censoring. Multivariate age-stratified Cox regression models were controlled for history of hypertension, diabetes, myocardial infarction, cancer, and major depression. RESULTS: Adjusted survival functions estimated 61% survival (54-69%, 95% C.I.) for those with sleep less than 300 min and 78% survival (73-85%, 95% C.I.) for those with actigraphic sleep longer than 390 min, as compared with survival of 90% (85-94%, 95% C.I.) for those with sleep of 300-390 min. Time-in-bed, sleep efficiency and the timing of melatonin metabolite excretion were also significant mortality risk factors. CONCLUSION: This study confirms a U-shaped relationship between survival and actigraphically measured sleep durations, with the optimal objective sleep duration being shorter than the self-report optimums. People who sleep five or six hours may be reassured. Further studies are needed to identify any modifiable factors for this mortality and possible approaches to prevention.

Self-reported sleep latency in postmenopausal women.

The aim of this study was to access how self-reported sleep latency (SRSL) was affected by sleep habits, mood, and circadian rhythm in postmenopausal women. Subjects (n=384, 67.9+/-7.7 yr) completed sleep and mood questionnaires, sleep log and actigraphic data. The major urinary melatonin metabolite (6-sulphatoxymelatonin, aMT6s) was assayed in fractional urine specimens for two 24-hr intervals. Although SRSL (26.5+/-24.4 min) and actigraphic sleep latency (ASL; 27.8+/-20.0 min) were correlated (r(s)=0.361, p<0.001), the short SRSLs tended to be underestimated whereas the long SRSLs tended to be overestimated as compared to ASL. SRSL was positively correlated with the scales of insomnia, mood and hot flash, hypertension, use of anti-hypertensive drugs and the acrophase and the offset of aMT6s. SRSL was negatively correlated with the global assessment of functioning scale in DSM-IV (GAF scale), and light exposure and wrist activity. Multiple linear regression analysis showed that the best-fit model to predict SRSL was light exposure, GAF scale, and use of anti-hypertensive drugs. SRSL may be determined by psychophysiological factors as well as circadian rhythm function. Therapeutic approaches suggested for trouble falling asleep might include increased daylight exposure, improvements in general health, and modification of anti-hypertensive pharmacotherapy.

Ethnicity, sleep, mood, and illumination in postmenopausal women.

BACKGROUND: This study examined how ethnic differences in sleep and depression were related to environmental illumination and circadian rhythms. METHODS: In an ancillary study to the Women's Health Initiative, 459 postmenopausal women were recorded for one week in their homes, using wrist monitors. Sleep and illumination experience were estimated. Depression was self-rated with a brief adjective check list. Affective diagnoses were made using the SCID interview. Sleep disordered breathing was monitored with home pulse oximetry. RESULTS: Hispanic and African-American women slept less than European-American women, according to both objective recordings and their own sleep logs. Non-European-American women had more blood oxygen desaturations during sleep, which accounted for 26% of sleep duration variance associated with ethnicity. Hispanic women were much more depressed. Hispanic, African-American and Native-American women experienced less daily illumination. Less daily illumination experience was associated with poorer global functioning, longer but more disturbed sleep, and more depression. CONCLUSIONS: Curtailed sleep and poor mood were related to ethnicity. Sleep disordered breathing was a factor in the curtailed sleep of minority women. Less illumination was experienced by non-European-American women, but illumination accounted for little of the contrasts between ethnic groups in sleep and mood. Social factors may be involved.

Melatonin excretion with affect disorders over age 60.

Numerous studies have reported low melatonin secretion in depression, but other studies have suggested no deficit or an increase. Alterations of circadian phase or duration of melatonin secretion have also been described. Since melatonin secretion decreases as we age, it seemed interesting to examine melatonin and depression in an aging sample. Volunteers who complained of mood or sleep problems were recruited for studies in which fractional urine specimens were collected for 24 h, both at home and in the laboratory. The major metabolite, 6-sulfatoxymelatonin (aMT6s), was determined by radioimmunoassay. Of 72 volunteers aged 60-78 years, seven had current major depression and 55% had a lifetime history of an affective disorder. A 55-fold range of home aMT6s excretion rates was observed. A lifetime history of any affective disorder was significantly associated with greater log(10)[mesor] aMT6s excretion in home collections and laboratory collections, but current affective disorders were neither significantly related to melatonin excretion nor to aMT6s acrophase timing, onset, offset or duration. These results are only weakly consistent with a photoperiodic hypothesis of depression.

Depression and endogenous melatonin in postmenopausal women.

BACKGROUND: Previous reports on melatonin secretion in depression are numerous but conflicting. There are very few studies relating the duration of the nocturnal melatonin peak to depression, and the results of those studies have been equivocal. METHODS: We studied mood disorders and urinary melatonin excretion in 382 postmenopausal women. Psychiatric diagnoses and global assessment of functioning (GAF) scores were determined based on a Structured Clinical Interview for DSM-IV Axis I Disorders (SCID). Urinary 6-sulfatoxymelatonin (6-SMT) samples were collected for two 24-h periods at home. RESULTS: A positive family history of depression was significantly related to a longer duration of 6-SMT excretion. There were marginally significant associations between current major depression and delayed offset of 6-SMT excretion and between later acrophase and lifetime major depression, even with control for age, ethnicity, season, and several medications. LIMITATIONS: The subjects were studied in their home environments, where light effects were not controlled. Data were restricted to postmenopausal women, including a limited number of subjects with current major depression. CONCLUSIONS: These results suggest that there might be a familial vulnerability in the endogenous melatonin signal in subjects prone to depression, and an abnormality in the duration of the melatonin signal in those with current major depression.

Effect of light treatment on sleep and circadian rhythms in demented nursing home patients.

OBJECTIVES: To determine whether fragmented sleep in nursing home patients would improve with increased exposure to bright light. DESIGN: Randomized controlled trial. SETTING: Two San Diego-area nursing homes. PARTICIPANTS: Seventy-seven (58 women, 19 men) nursing home residents participated. Mean age +/- standard deviation was 85.7 +/- 7.3 (range 60-100) and mean Mini-Mental State Examination was 12.8 +/- 8.8 (range 0-30). INTERVENTIONS: Participants were assigned to one of four treatments: evening bright light, morning bright light, daytime sleep restriction, or evening dim red light. MEASUREMENTS: Improvement in nighttime sleep quality, daytime alertness, and circadian activity rhythm parameters. RESULTS: There were no improvements in nighttime sleep or daytime alertness in any of the treatment groups. Morning bright light delayed the peak of the activity rhythm (acrophase) and increased the mean activity level (mesor). In addition, subjects in the morning bright light group had improved activity rhythmicity during the 10 days of treatment. CONCLUSION: Increasing exposure to morning bright light delayed the acrophase of the activity rhythm and made the circadian rhythm more robust. These changes have the potential to be clinically beneficial because it may be easier to provide nursing care to patients whose circadian activity patterns are more socially acceptable.

Mortality associated with sleep duration and insomnia.

BACKGROUND: Patients often complain about insufficient sleep or chronic insomnia in the belief that they need 8 hours of sleep. Treatment strategies may be guided by what sleep durations predict optimal survival and whether insomnia might signal mortality risks. METHODS: In 1982, the Cancer Prevention Study II of the American Cancer Society asked participants about their sleep duration and frequency of insomnia. Cox proportional hazards survival models were computed to determine whether sleep duration or frequency of insomnia was associated with excess mortality up to 1988, controlling simultaneously for demographics, habits, health factors, and use of various medications. RESULTS: Participants were more than 1.1 million men and women from 30 to 102 years of age. The best survival was found among those who slept 7 hours per night. Participants who reported sleeping 8 hours or more experienced significantly increased mortality hazard, as did those who slept 6 hours or less. The increased risk exceeded 15% for those reporting more than 8.5 hours sleep or less than 3.5 or 4.5 hours. In contrast, reports of "insomnia" were not associated with excess mortality hazard. As previously described, prescription sleeping pill use was associated with significantly increased mortality after control for reported sleep durations and insomnia. CONCLUSIONS: Patients can be reassured that short sleep and insomnia seem associated with little risk distinct from comorbidities. Slight risks associated with 8 or more hours of sleep and sleeping pill use need further study. Causality is unproven.

Exercise and Survival in the Very Old.

Risk factors that are strongly associated with cardiovascular events in middle age are less predictive in the elderly. These reduced associations are most evident after about age 75 years. Exercise has been associated with survival in middle-aged men; data are sparse on its relation to survival in the very old. This association was tested in a community-dwelling cohort of 440 men and 457 women aged 75 years or older who were followed prospectively for an average of 5 years. In age-adjusted proportional hazards models, current regular exercise at least 3 times per week was strongly associated with survival in men (relative risk for death 0.54, P is less than.01) and women (relative risk 0.45, P is less than.01). Results were unchanged after adjustment for physical and emotional health status, or when persons with heart disease at baseline were excluded. Results were also unchanged after adjustment for change in exercise level compared with 10 years ago, and for conventional cardiovascular risk factors (blood pressure, lipid concentration, glucose levels, and smoking).