Polysomnographic Sleep and Circadian Temperature Rhythms as a Function of Prior Shift Work Exposure in Retired Seniors.

In an earlier published telephone interview study (n > 1,000) we have shown that retired shift workers subjectively report worse sleep than retired day workers. This laboratory study sought to determine whether these findings held up when objective polysomnograhic (PSG) measures of sleep were taken and whether retirees' circadian temperature rhythms differed as a function of shift work exposure. All completers of the telephone interview were invited to attend a 36-hour laboratory study for which participants were paid. This involved continuous core body temperature measurement (using an ingestible pill-based system) and 2 nights of PSG. Shift work exposure (plus other measures) was collected by taking a detailed work history. The second laboratory night was scored into sleep stages. Post hoc, we divided participants into 4 shift work exposure groups: 0 years (ie, no exposure to shift work), 1 to 7 years, 7 to 20 years, and >20 years. Sample sizes were 11, 16, 15, and 15, respectively, with approximate equality in mean age (71.7 years of age, 69.1 years of age, 70.0 years of age, and 70.4 years of age, respectively) and percent male (63%, 50%, 67%, and 73%, respectively). Shift work exposure was associated with worse PSG sleep in a dose-related fashion. The percentages of participants with sleep efficiency, 80% for the 0 years, 1 to 7 years, 7 to 20 years, and >20 years groups were 36%, 63%, 67%, and 73%, respectively (P < 0.01), and the percentages with total sleep time (TST), 6 hours were 36%, 56%, 53%, and 73%, respectively (P < 0.01). From the circadian rhythm record, shift work exposure appeared to result (P = 0.06) in an increased spread of phase angles (difference between habitual bedtime and time of temperature trough). In conclusion, it appears likely that shift work may be related to a scarring of sleep and circadian rhythms. This may be associated with a change in the relationship between habitual sleep timing and the phase of the circadian pacemaker.

Shiftworkers report worse sleep than day workers, even in retirement.

The aim of this study was to explore how the level of shiftwork exposure during an individual's working life might be related to subjectively reported sleep quality and timing during retirement. Telephone interviews regarding past employment and sleep timing and quality (among other variables) were conducted using a pseudo-random age-targeted sampling process. Subjective sleep quality was assessed using a telephone version of the Pittsburgh Sleep Quality Index. Timing of reported habitual bedtimes and rise-times were assessed using the Sleep Timing Questionnaire. Questions measuring morningness and subjective health were also given. Retired seniors (aged >65 years, n = 1113) were studied. Analysis was by analysis of variance, with shiftwork exposure in three bins [0 (n = 387), 1-15 (n = 371) and >15 years (n = 355)], gender (n = 634 male, 479 female) and former occupation [in two broad categories, 'managerial' (n = 437) versus 'other' (n = 676)] as factors. In retired shiftworkers, relative to retired day workers, past exposure to shiftwork was associated with higher (worse) PSQI scores by 1.0 units (1-15 years) and 0.6 units (>15 years) (main effect P = 0.005). There were also main effects of gender and former occupation (males and managerials reporting better sleep), but neither variable interacted with shiftwork exposure. The timing of current mean habitual bedtimes and rise-times (and also the variance around them) were very similar for the three shiftwork exposure groups. The shiftwork exposure effect did not appear to be mediated by either morningness or current health. Prior exposure to shiftwork would appear to be related to currently reported sleep problems during retirement.

Circadian type and bed-timing regularity in 654 retired seniors: correlations with subjective sleep measures.

STUDY OBJECTIVES: Using telephone interview data from retired seniors to explore how inter-individual differences in circadian type (morningness) and bed-timing regularity might be related to subjective sleep quality and quantity. DESIGN: MANCOVA with binary measures of morningness, stability of bedtimes, and stability of rise-times as independent variables; sleep measures as dependent variables; age, former shift work, and gender as covariates. SETTING: Telephone interviews using a pseudo-random age-targeted sampling process. PARTICIPANTS: 654 retired seniors (65 y+, 363M, 291F). INTERVENTION: none. INDEPENDENT VARIABLES: (1) circadian type (from Composite Scale of Morningness [CSM]), and stability of (2) bedtime and (3) rise-time from the Sleep Timing Questionnaire (STQ). DEPENDENT VARIABLES: Pittsburgh Sleep Quality Index (PSQI) score, time in bed, time spent asleep, and sleep efficiency, from Sleep Timing Questionnaire (STQ). Morning-type orientation, stability in bedtimes, and stability in rise-times were all associated with better sleep quality (P < 0.001, for all; effect sizes: 0.43, 0.33, and 0.27). Morningness was associated with shorter time in bed (P < 0.0001, effect size 0.45) and time spent asleep (P < 0.005, effect size 0.26). For bedtime and rise-time stability the direction of effect was similar but mostly weaker. CONCLUSIONS: In retired seniors, a morning-type orientation and regularity in bedtimes and rise-times appear to be correlated with improved subjective sleep quality and with less time spent in bed.

Efficacy of brief behavioral treatment for chronic insomnia in older adults.

BACKGROUND: Chronic insomnia is a common health problem with substantial consequences in older adults. Cognitive behavioral treatments are efficacious but not widely available. The aim of this study was to test the efficacy of brief behavioral treatment for insomnia (BBTI) vs an information control (IC) condition. METHODS: A total of 79 older adults (mean age, 71.7 years; 54 women [70%]) with chronic insomnia and common comorbidities were recruited from the community and 1 primary care clinic. Participants were randomly assigned to either BBTI, consisting of individualized behavioral instructions delivered in 2 intervention sessions and 2 telephone calls, or IC, consisting of printed educational material. Both interventions were delivered by a nurse clinician. The primary outcome was categorically defined treatment response at 4 weeks, based on sleep questionnaires and diaries. Secondary outcomes included self-report symptom and health measures, sleep diaries, actigraphy, and polysomnography. RESULTS: Categorically defined response (67% [n = 26] vs 25% [n = 10]; χ(2) = 13.8) (P < .001) and the proportion of participants without insomnia (55% [n = 21] vs 13% [n = 5]; χ(2) = 15.5) (P < .001) were significantly higher for BBTI than for IC. The number needed to treat was 2.4 for each outcome. No differential effects were found for subgroups according to hypnotic or antidepressant use, sleep apnea, or recruitment source. The BBTI produced significantly better outcomes in self-reported sleep and health (group × time interaction, F(5,73) = 5.99, P < .001), sleep diary (F(8,70) = 4.32, P < .001), and actigraphy (F(4,74) = 17.72, P < .001), but not polysomnography. Improvements were maintained at 6 months. CONCLUSION: We found that BBTI is a simple, efficacious, and durable intervention for chronic insomnia in older adults that has potential for dissemination across medical settings. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT00177203.

Effects of a two-hour change in bedtime on the sleep of healthy seniors.

Some of the sleep disruption seen in seniors (>65 yrs) may be due to alteration of the circadian pacemaker phase and/or its phase angle with bedtime. The purpose of this study was to determine the effects of 2 h changes in the timing of bedtime (both earlier and later) on the sleep of seniors. Ten healthy seniors (9 F, 1 M, age 70-82 yrs) were each studied individually during three 120 h sessions (each separated by >2 weeks) in a time-isolation laboratory. On nights 1 and 2, bedtime and rise-time occurred at the subjects' habitual times; on nights 3-5, bedtime was specified by the experiment, but rise-time was at the subjects' discretion (without knowledge of clock time). Under the control condition, subjects went to bed at their habitual bedtime (HBT), under the earlier bedtime condition at (HBT-2 h), and under the later bedtime condition at (HBT+2 h). Sleep was polysomnnographically recorded and rectal temperature continuously monitored. Although total sleep time increased in the earlier compared to the later condition (p<0.01), sleep efficiency decreased and wake after sleep onset increased (p<0.01). Subjective ratings of sleep were also worse under the earlier (HBT-2 h) than under later (HBT+ 2 h) condition (p<0.05). Performance did not differ between the earlier and later conditions. The larger the phase angle between actual bedtime and circadian temperature minimum (Tmin), the longer the time spent in bed and total sleep time, and the worse the sleep efficiency and subjective sleep ratings. There were no effects related to the phase angle between Tmin and rise-time. The relative benefits of longer vs. more efficient sleep in the elderly require further investigation.

Sleep and circadian rhythms in spousally bereaved seniors.

A laboratory study of sleep and circadian rhythms was undertaken in 28 spousally bereaved seniors (> or =60 yrs) at least four months after the loss event. Measures taken included two nights of polysomnography (second night used), approximately 36 h of continuous core body temperature monitoring, and four assessments of mood and alertness throughout a day. Preceding the laboratory study, two-week diaries were completed, allowing the assessment of lifestyle regularity using the 17-item Social Rhythm Metric (SRM) and the timing of sleep using the Pittsburgh Sleep Diary (PghSD). Also completed were questionnaires assessing level of grief (Texas Revised Inventory of Grief [TRIG] and Index of Complicated Grief [ICG]), subjective sleep quality (Pittsburgh Sleep Quality Index [PSQI]), morningness-eveningness (Composite Scale of Morningness [CSM]), and clinical interview yielding a Hamilton Depression Rating Scale (HDRS) score. Grief was still present, as indicated by an average TRIG score of about 60. On average, the bereaved seniors habitually slept between approximately 23:00 and approximately 06:40 h, achieving approximately 6 h of sleep with a sleep efficiency of approximately 80%. They took about 30 min to fall asleep, and had their first REM episode after 75 min. About 20% of their sleep was in Stage REM, and about 3% in Stages 3 or 4 (slow wave sleep). Their mean PSQI score was 6.4. Their circadian temperature rhythms showed the usual classic shape with a trough at approximately 01:00 h, a fairly steep rise through the morning hours, and a more gradual rise to mid-evening, with an amplitude of approximately 0.8 degrees C. In terms of lifestyle regularity, the mean regularity (SRM) score was 3.65 (slightly lower than that usually seen in seniors). Mood and alertness showed time-of-day variation with peak alertness in the late morning and peak mood in the afternoon. Correlations between outcome sleep/circadian variables and level of grief (TRIG score) were calculated; there was a slight trend for higher grief to be associated with less time spent asleep (p=0.07) and reduced alertness at 20:00 h (p=0.05). Depression score was not correlated with TRIG score (p>0.20). When subjects were divided into groups by the nature of their late spouse's death (expected/after a long-term chronic illness [n=18] versus unexpected [n=10]), no differences emerged in any of the variables. In conclusion, when studied at least four months after the loss event, there appears to be some sleep disruption in spousally bereaved seniors. However, this disruption does not appear to be due to bereavement-related disruptions in the circadian system.