Objectively measured daytime sleepiness predicts weight change among adults: Findings from the Wisconsin Sleep Cohort Study.

OBJECTIVE: Body mass index (BMI) trajectories are associated with night-time sleep, but it is not clear how they relate to daytime sleepiness in population data. This study aimed to examine longitudinal associations between levels and changes in daytime sleepiness and BMI trajectories among men and women. METHODS: We estimated growth curve models among 827 participants in the Wisconsin Sleep Cohort Study (mean [sd] age = 55.2 [8.0] years at baseline). The outcome variable was BMI (kg/m2) and the key predictor was daytime sleepiness measured by Multiple Sleep Latency Test (MSLT) scores. Covariates included demographics, health behaviors, retirement status, stimulant use, and depressive symptoms. In sensitivity analyses, we evaluated the potential effects of cardiovascular disease, shift work status, and sleep apnea on the robustness of sleepiness and BMI associations. RESULTS: At the between-person level, men who were sleepier had higher BMI levels. At the within-person level, age moderated the positive association between sleepiness and BMI among women. Specifically, young women who became sleepier over time gained more BMI than older women with comparable increases in sleepiness. Furthermore, while BMI tended to increase with age among women, BMI trajectories were steeper among sleepy women than among well-rested women, who experienced less increase in BMI over time. CONCLUSION: The study suggested that levels and changes in daytime sleepiness as objectively measured by MSLT scores are associated with body mass among adults.

Prevalence and Course of Idiopathic Hypersomnia in the Wisconsin Sleep Cohort Study.

BACKGROUND AND OBJECTIVES: Idiopathic hypersomnia (IH) is a CNS disorder of hypersomnolence of unknown etiology. Due to the requirement for objective sleep testing to diagnose the disorder, there are currently no population-based estimates of the prevalence of IH nor data regarding the longitudinal course of IH in naturalistic settings. METHODS: Subjective and objective data from the Wisconsin Sleep Cohort study were used to identify cases with probable IH from participants with polysomnography and multiple sleep latency test data. Demographic, polysomnographic, and symptom-level data were compared between those with and without IH. Longitudinal trajectories of daytime sleepiness among those with IH were assessed to evaluate symptom persistence or remission over time. RESULTS: From 792 cohort study participants with available polysomnography and multiple sleep latency test data, 12 cases with probable IH were identified resulting in an estimated prevalence of IH of 1.5% (95% CI 0.7-2.5, p < 0.0001). Consistent with inclusion/exclusion criteria, cases with IH had more severe sleepiness and sleep propensity, despite similar or longer sleep times. Longitudinal data (spanning 12.1 ± 4.3 years) demonstrated a chronic course of sleepiness for most of the cases with IH, though pathologic somnolence remitted in roughly 40% of cases. DISCUSSION: These results demonstrate IH is more common in the working population than generally assumed with a prevalence on par with other common neurologic and psychiatric conditions. Further efforts to identify and diagnose those impaired by unexplained daytime somnolence may help clarify the causes of IH and the mechanisms underlying symptomatic remission.

Associations of gut microbiome richness and diversity with objective and subjective sleep measures in a population sample.

STUDY OBJECTIVES: Alterations in gut microbiota composition have been associated with several conditions, and there is emerging evidence that sleep quantity and quality are associated with the composition of the gut microbiome. Therefore, this study aimed to assess the associations between several measures of sleep and the gut microbiome in a large, population-based sample. METHODS: Data were collected from participants in the Survey of the Health of Wisconsin from 2016 to 2017 (N = 720). Alpha diversity was estimated using Chao1 richness, Shannon's diversity, and Inverse Simpson's diversity. Beta diversity was estimated using Bray-Curtis dissimilarity. Models for each of the alpha-diversity outcomes were calculated using linear mixed effects models. Permutational multivariate analysis of variance tests were performed to test whether gut microbiome composition differed by sleep measures. Negative binomial models were used to assess whether sleep measures were associated with individual taxa relative abundance. RESULTS: Participants were a mean (SD) age of 55 (16) years and 58% were female. The sample was 83% non-Hispanic white, 10.6% non-Hispanic black, and 3.5% Hispanic. Greater actigraphy-measured night-to-night sleep duration variability, wake-after-sleep onset, lower sleep efficiency, and worse self-reported sleep quality were associated with lower microbiome richness and diversity. Sleep variables were associated with beta-diversity, including actigraphy-measured night-to-night sleep duration variability, sleep latency and efficiency, and self-reported sleep quality, sleep apnea, and napping. Relative abundance of several taxa was associated with night-to-night sleep duration variability, average sleep latency and sleep efficiency, and sleep quality. CONCLUSIONS: This study suggests that sleep may be associated with the composition of the gut microbiome. These results contribute to the body of evidence that modifiable health habits can influence the human gut microbiome.

Cardiorespiratory Fitness Attenuates the Deleterious Effects of Sleep Apnea on Cerebral Structure and Perfusion in the Wisconsin Sleep Cohort Study.

BACKGROUND: Emerging evidence suggests that age-related changes in cerebral health may be sensitive to vascular risk modifiers, such as physical activity and sleep. OBJECTIVE: We examine whether cardiorespiratory fitness modifies the association of obstructive sleep apnea (OSA) severity with MRI-assessed measures of cerebral structure and perfusion. METHODS: Using data from a cross-sectional sample of participants (n = 129, 51% female, age range 49.6-85.3 years) in the Wisconsin Sleep Cohort study, we estimated linear models of MRI-assessed total and regional gray matter (GM) and white matter (WM) volumes, WM hyperintensity (WMH:ICV ratio), total lesion volume, and arterial spin labeling (ASL) cerebral blood flow (CBF), using an estimated measure of cardiorespiratory fitness (CRF) and OSA severity as predictors. Participants' sleep was assessed using overnight in-laboratory polysomnography, and OSA severity was measured using the apnea-hypopnea index (AHI), or the mean number of recorded apnea and hypopnea events per hour of sleep. The mean±SD time difference between PSG data collection and MRI data collection was 1.7±1.5 years (range: [0, 4.9 years]). RESULTS: OSA severity was associated with reduced total GM volume (ß=-0.064; SE = 0.023; p = 0.007), greater total WM lesion volume (interaction p = 0.023), and greater WMHs (interaction p = 0.017) in less-fit subjects. Perfusion models revealed significant differences in the association of AHI and regional CBF between fitness groups (interaction ps < 0.05). CONCLUSION: This work provides new evidence for the protective role of cardiorespiratory fitness against the deleterious effects of OSA on brain aging in late-middle age to older adults.

The genetic etiology of periodic limb movement in sleep.

STUDY OBJECTIVES: Periodic limb movement in sleep is a common sleep phenotype characterized by repetitive leg movements that occur during or before sleep. We conducted a genome-wide association study (GWAS) of periodic limb movements in sleep (PLMS) using a joint analysis (i.e., discovery, replication, and joint meta-analysis) of four cohorts (MrOS, the Wisconsin Sleep Cohort Study, HypnoLaus, and MESA), comprised of 6843 total subjects. METHODS: The MrOS study and Wisconsin Sleep Cohort Study (N = 1745 cases) were used for discovery. Replication in the HypnoLaus and MESA cohorts (1002 cases) preceded joint meta-analysis. We also performed LD score regression, estimated heritability, and computed genetic correlations between potentially associated traits such as restless leg syndrome (RLS) and insomnia. The causality and direction of the relationships between PLMS and RLS was evaluated using Mendelian randomization. RESULTS: We found 2 independent loci were significantly associated with PLMS: rs113851554 (p = 3.51 × 10-12, ß = 0.486), an SNP located in a putative regulatory element of intron eight of MEIS1 (2p14); and rs9369062 (p = 3.06 × 10-22, ß = 0.2093), a SNP located in the intron region of BTBD9 (6p12); both of which were also lead signals in RLS GWAS. PLMS is genetically correlated with insomnia, risk of stroke, and RLS, but not with iron deficiency. Pleiotropy adjusted Mendelian randomization analysis identified a causal effect of RLS on PLMS. CONCLUSIONS: Because PLMS is more common than RLS, PLMS may have multiple causes and additional studies are needed to further validate these findings.

Association between stressful life events and non-optimal lipid levels among women with hyperlipidaemia.

AIMS: Psychological stress has been linked to lipid dysregulation with noticeable gender differences, but it remains unclear whether women are more susceptible to non-optimal lipid levels than men, when experiencing stressful life events. This study aims to examine the association between stressful life events and non-optimal lipid levels among persons with hyperlipidaemia and whether the association differs between men and women. METHODS AND RESULTS: A nested case-control study was performed using data from the Wisconsin Sleep Cohort (WSC) Study from 2011 to 2015, including 224 participants with hyperlipidaemia and without a history of myocardial infarction or heart failure. Among them, 63 participants with non-optimal LDL cholesterol or triglyceride levels were identified as cases, and 161 participants with optimal LDL cholesterol and triglyceride levels were identified as controls. Cases and controls were traced back to their self-reported life events collected through the Retirement and Sleep Trajectories study during 2010-11. The association between stressful life events and non-optimal lipid levels was examined using multivariable logistic regression; confounding effects were addressed using propensity score weighting and Mahalanobis distance matching; gender differences were examined using subgroup analysis. Results showed that a higher number of stressful life events during 2010-11 was associated with greater odds of non-optimal lipid levels during 2011-15 (odds ratio = 1.45, P = 0.03) among women with hyperlipidaemia, whereas the association was not significant among men with hyperlipidaemia (P = 0.910). CONCLUSION: Future studies are needed to examine the underlying mechanisms that explain gender differences in the association between stressful life events and non-optimal lipid levels. REGISTRATION: ClinicalTrials.gov NCT00005557.

Metabolic health disparities driven by financial stress: Behavioural adaptation or modification?

Financial stress has been linked to an increased risk of metabolic syndrome, yet, it remains unclear whether suboptimal sleep duration and physical inactivity are the adaptive responses to financial stress or effect modifiers in the association between financial stress and metabolic syndrome. Hence, this study aims to examine whether physical activity and sleep duration mediate or moderate the bivariate association between financial stress and metabolic syndrome. A prospective secondary analysis was conducted using data from the Wisconsin Sleep Cohort Study (N = 445, mean [SD] age = 64 [7] years). Baseline moderation effect was examined using subgroup analysis with model constraints; prospective mediation model was examined using bias-corrected bootstrap confidence intervals. Results indicate that participants with higher financial stress were less likely to meet physical activity and sleep recommendations. Baseline moderation analysis indicates that meeting current recommendations of sleep duration and physical activity attenuated the association between financial stress and metabolic syndrome. In the prospective mediation analysis, weekly physical activity levels partially mediated the relationship between financial stress and metabolic syndrome, but sleep duration did not mediate this relationship. In conclusion, the joint effect of optimal sleep duration and physical activity disassociates financial stress from the risk of metabolic syndrome. Future interventions addressing metabolic risk might achieve better outcomes if clinicians and researchers factor in the behavioral adaptation of physical inactivity in financially stressed adults (Clinical Trial Registration: NCT00005557).

Genetic risk for subjective reports of insomnia associates only weakly with polygraphic measures of insomnia in 2,770 adults.

STUDY OBJECTIVES: Subjective insomnia complaints and objective sleep changes are mostly studied outside of clinical trial studies. In this study, we tested whether 240 genetic variants associated with subjectively reported insomnia were also associated with objective insomnia parameters extracted from polysomnographic recordings in three studies. METHODS: The study sample (total n = 2,770) was composed of the Wisconsin Sleep Cohort (n = 1,091) and the Osteoporotic Fractures in Men (n = 1,026) study, two population-based studies, and the Stanford Sleep Cohort, a sleep center patient-based sample (n = 653). Seven objective polysomnographic features related to insomnia defined outcome variables, with each variant allele serving as predictor. Meta-regression was performed, accounting for common confounders as well as variance differences between studies. Additionally, a normalized genetic risk score was generated for each subject to serve as a predictor variable in separate linear mixed models assessing objective insomnia features. RESULTS: After correction for multiple testing, single-nucleotide polymorphisms associated with subjective insomnia were not significantly associated with 6 of 7 objective sleep measures. Only periodic limb movement index was significantly associated with rs113851554 (MEIS1), as found in previous studies. The normalized genetic risk score was only weakly associated with arousal index and duration of wake after sleep onset. CONCLUSIONS: Our findings suggest that subjective insomnia does not have a strong genetic signature mapping onto objective (polysomnographic) sleep variables. CITATION: Foldager J, Peppard PE, Hagen EW, et al. Genetic risk for subjective reports of insomnia associates only weakly with polygraphic measures of insomnia in 2,770 adults. J Clin Sleep Med. 2022;18(1):21-29.

Habitual sleep, sleep duration differential, and weight change among adults: Findings from the Wisconsin Sleep Cohort Study.

OBJECTIVES: Assess longitudinal associations between diary-measured sleep duration and clinically assessed body mass index (BMI). DESIGN: Multilevel growth curve analyses examined how within-person changes and between-person differences in habitual sleep duration were associated with BMI trajectories. SETTING: Sleep diaries across 2-6 consecutive weekday and weekend nights at each data collection point, repeatedly collected at approximate 4-year intervals, for an average of 9.2 (standard deviation [SD] = 3.6) years between 1989 and 2011. PARTICIPANTS: About 784 participants (47% women) enrolled in the Wisconsin Sleep Cohort Study (mean [SD] age = 51.1 [8.0] years at baseline). MEASUREMENTS: The outcome variable was BMI (kg/m2). Key predictors were habitual sleep duration (defined as average weekday nighttime sleep duration) and sleep duration differential (defined as the difference between average weekday and average weekend nighttime sleep duration) at each data collection wave. RESULTS: Men with shorter habitual sleep duration on weekdays had higher BMI than men with longer habitual sleep duration on weekdays (ß = -0.90 kg/m2/hour, se = 0.34, p = .008). Participants with larger differentials between weekday and weekend sleep duration experienced more rapid BMI gain over time for both men (ß = 0.033 kg/m2/year per hour differential, se = 0.017, p = .044) and women (ß = 0.057 kg/m2/year per hour differential, se = 0.027, p = .036). CONCLUSION: This study suggests that habitual short sleep is associated with higher BMI levels in men and that a larger weekday-weekend sleep differential is associated with increasing BMI trajectories among both men and women in mid-to-late life.

Polysomnographic indicators of restorative sleep and body mass trajectories in the Wisconsin Sleep Cohort Study.

STUDY OBJECTIVES: Previous research suggests that reductions in restorative, slow-wave (N3), and rapid eye movement (REM) sleep are associated with weight gain and obesity in mid-to-late life. We extend prior work by examining how within-person (WP) changes and between-person (BP) differences in restorative sleep over several years are associated with body mass trajectories among participants in the Wisconsin Sleep Cohort Study (WSCS). METHODS: We used data from 4,862 polysomnographic (PSG) sleep studies and physical exams collected from 1,187 WSCS participants over an average duration of 14.9 years. Primary measures of interest included body mass index (BMI = kg/m2) and the percentages of time spent in N3 and REM sleep. We estimated a series of linear mixed regression models to examine how WP changes and BP differences in N3 and REM sleep affected BMI trajectories, controlling for other sleep measures, demographic characteristics, and health behaviors as potential confounders. RESULTS: Women in the WSCS experienced more rapid BMI gain than men. With some variation by sex, we found that (1) below-average N3 and REM sleep is associated with above-average BMI, and (2) within-person decreases in N3 and REM sleep over time are associated with gains in BMI. These findings persisted after adjustment for sleep duration and other potential confounders. CONCLUSIONS: Our findings highlight the importance of PSG indices of restorative sleep in mid-to-late life, suggesting that future clinical treatments and public health policies will benefit from heightened attention to sleep quality.

Physiological sleep measures predict time to 15-year mortality in community adults: Application of a novel machine learning framework.

Clarifying whether physiological sleep measures predict mortality could inform risk screening; however, such investigations should account for complex and potentially non-linear relationships among health risk factors. We aimed to establish the predictive utility of polysomnography (PSG)-assessed sleep measures for mortality using a novel permutation random forest (PRF) machine learning framework. Data collected from the years 1995 to present are from the Sleep Heart Health Study (SHHS; n = 5,734) and the Wisconsin Sleep Cohort Study (WSCS; n = 1,015), and include initial assessments of sleep and health, and up to 15 years of follow-up for all-cause mortality. We applied PRF models to quantify the predictive abilities of 24 measures grouped into five domains: PSG-assessed sleep (four measures), self-reported sleep (three), health (eight), health behaviours (four), and sociodemographic factors (five). A 10-fold repeated internal validation (WSCS and SHHS combined) and external validation (training in SHHS; testing in WSCS) were used to compute unbiased variable importance metrics and associated p values. We observed that health, sociodemographic factors, and PSG-assessed sleep domains predicted mortality using both external validation and repeated internal validation. The PSG-assessed sleep efficiency and the percentage of sleep time with oxygen saturation <90% were among the most predictive individual measures. Multivariable Cox regression also revealed the PSG-assessed sleep domain to be predictive, with very low sleep efficiency and high hypoxaemia conferring the highest risk. These findings, coupled with the emergence of new low-burden technologies for objectively assessing sleep and overnight oxygen saturation, suggest that consideration of physiological sleep measures may improve risk screening.

Gender Differences in the Relationship Between Financial Stress and Metabolic Abnormalities.

BACKGROUND: Financial stress is associated with higher prevalence of metabolic abnormalities and cardiovascular disease, but the extent to which this association differs by type of metabolic abnormalities or gender is unclear. OBJECTIVES: The study aims were (a) to examine the association between financial stress and the prevalence of common metabolic abnormalities and (b) to test the association for gender differences. METHODS: A cross-sectional secondary analysis was conducted using data from the Retirement and Sleep Trajectories study, an ancillary study of the Wisconsin Sleep Cohort study. Composite indicator structural equation alpha modeling with a stacking approach was applied in the data analysis. RESULTS: After controlling for covariates, financial stress was positively associated with the prevalence of abdominal obesity, metabolic syndrome, and dyslipidemia, with significant gender differences. Among men, financial stress was positively associated with the prevalence of hypertriglyceridemia. Among women, financial stress was positively associated with the prevalence of prediabetes, abdominal obesity, metabolic syndrome, and dyslipidemia. CONCLUSION: Men living with financial stress are more likely to have hypertriglyceridemia, a specific metabolic abnormality and risk factor for acute cardiovascular events. However, financial stress in women is associated with a broader array of metabolic abnormalities (e.g., dyslipidemia, prediabetes, abdominal obesity, metabolic syndrome), highlighting a potential risk of multiple chronic conditions later in life.

A Comparison of Self- and Proxy-Reported Subjective Sleep Durations With Objective Actigraphy Measurements in a Survey of Wisconsin Children 6-17 Years of Age.

Children's sleep quality and duration are important to overall development, health, and wellbeing. However, measuring children's sleep is challenging, especially in situations where objective assessment is impractical. This study aimed to assess age and proxy effects in comparing subjective sleep duration with objective measures, in a community-based sample of Wisconsin children (aged 6-17 years), recruited from 2014-2017. The sample participants had a mean age of 11.4 (standard deviation, 3.3) years and 52% of them were male. We used linear mixed effects models to test for age effects in proxy- and self-report groups separately, and a quasiexperimental regression discontinuity approach to compare subjective sleep duration with objective actigraphy estimates across proxy- and self-report groups. We found evidence of systematic overestimation of sleep duration when using subjective measurements but did not find evidence of age effects in either group. Based on these analyses, we found evidence of differential overestimation by proxy- or self-report condition. Proxy reporters overestimated sleep duration by 2.3 hours (95% confidence interval: 2.2, 2.4), compared with 1.0 hour (95% confidence interval: 0.7, 1.2) for self-reporters. These findings suggest that proxy- versus self-reporting conditions are an important consideration when designing a study, and that it might be beneficial to reduce the age at which children self-report.

Longitudinal sleep characteristics and hypertension status: results from the Wisconsin Sleep Cohort Study.

AIMS: Sleep characteristics such as short sleep duration or sleep-disordered breathing are established predictors of hypertension. However, few studies have used in-lab polysomnography with a longitudinal design to measure how hypertension is associated with different sleep stages over time. The purpose of this study is to examine whether hypertension is associated with the longitudinal course of sleep quality over time. METHODS: The current study evaluated data from the Wisconsin Sleep Cohort Study, which consists of 1525 adults in a community-based population of middle-aged to older adults followed for approximately 12-25 years. Sleep characteristics were objectively measured using polysomnography and subjectively assessed using a self-report questionnaire on insomnia complaints. We used linear mixed-effects regression models and cumulative logit models to assess whether the interaction of hypertension and time is associated with objective and subjective sleep. RESULTS: We found people with hypertension exhibited a greater decline in total sleep time in rapid eye movement sleep (%) over time than those without hypertension (P < 0.05). Individuals with hypertension had less decline in % N3 sleep over time than those without hypertension (P < 0.05). Among the subjective insomnia complaints, our findings indicate hypertensive individuals have a higher probability of having higher levels of 'difficulties in falling asleep' compared with people without hypertension. CONCLUSION: These findings suggest that hypertension is associated with modified longitudinal changes of objective and subjective sleep characteristics.

Impaired neurobehavioral alertness quantified by the psychomotor vigilance task is associated with depression in the Wisconsin Sleep Cohort study.

BACKGROUND: Excessive daytime sleepiness plays an important role in the presentation and course of mood disorders. Standard objective measures of daytime sleep propensity are of little to no value in depressive illness. This study examined the psychomotor vigilance task (PVT), an objective measure of neurobehavioral alertness, and its cross-sectional and longitudinal associations with depressive symptomatology in the Wisconsin Sleep Cohort Study. METHODS: The sample consisted of 1569 separate 10-min PVT assessments conducted in 942 unique individuals. Cross-sectional and longitudinal conditional logistic regression models were used to estimate associations between the primary outcome of depression symptomatology (adjusted Zung scale≥50) and six separate PVT variables: mean reciprocal reaction time (1/RT); total lapses (RTs≥500 msec; LAPSE); total false responses (FALSE); reciprocal of the mean of the 10% fastest (FAST) and 10% slowest (SLOW) RTs; and slope of the linear regression line for all transformed 1/RTs (SLOPE). RESULTS: In fully-adjusted cross-sectional models, 1/RT, LAPSE, FAST, and SLOW were each significantly associated with depression, such that worse neurobehavioral alertness was associated with higher odds of depressive symptomatology. Similar, though attenuated, findings were observed in fully-adjusted conditional longitudinal models that examined within-subject changes in depression status in the subset of participants with repeated PVT assessments. FALSE and SLOPE were not associated with depression in either cross-sectional or conditional longitudinal models. CONCLUSIONS: These findings suggest components of the PVT are associated with depressive symptomatology. Further research is indicated to clarify the role of the PVT in the assessment of hypersomnolence in mood disorders.

Individuals' perceptions of social support from family and friends are associated with lower risk of sleep complaints and short sleep duration.

OBJECTIVE: To examine whether individuals' perceptions of social support (SS) from partners, other family members, and friends are associated with risk of sleep complaints and short sleep duration. METHODS: A cross-sectional and prospective study with 1,688 community dwelling adults from the Retirement and Sleep Trajectories study. Four annual, self-administered questionnaires were mailed to participants in the year 2010-2014. Self-reports of individuals' perceptions of SS were obtained at the baseline survey. Sleep quality and duration were self-reported on each of the four surveys over the follow-up. Associations were examined with mixed-effect models, controlling for confounders. RESULTS: In fully adjusted analyses, compared with those reporting low SS from their partner, the risk of reporting more than 1 sleep symptom was significantly lower among those with intermediate (relative risk, RR = 0.68; 95% confidence interval, CI = 0.53-0.87) and high SS (RR = 0.61; 95% CI=0.48-0.77). Similarly, relative to those with low SS, those reporting high SS from family (RR = 0.74; 95% CI = 0.57-0.94) and friends (RR = 0.73; 95% CI = 0.58-0.92) had lower risk of having more than 1 sleep symptom. Compared with those with low, intermediate (RR = 0.70; 95% CI = 0.52-0.96), and high SS (RR = 0.63; 95% CI = 0.48-0.84) from partners, intermediate (RR = 0.76; 95% CI = 0.59-0.97) and high SS (RR = 0.69; 95% CI = 0.51-0.92) from family and high SS (RR = 0.74; 95% CI = 0.56-0.99) from friends were associated with lower risk of short sleep (≤6 h). CONCLUSION: The perception of higher SS from relatives and friends is independently associated with lower risk of poor sleep quality and short sleep duration. Future research and intervention studies should test whether strengthening social relationships can positively effect sleep health.

Blood pressure dipping and sleep quality in the Wisconsin Sleep Cohort.

AIMS: Nondipping blood pressure (BP) is associated with higher risk for hypertension and advanced target organ damage. Insomnia is the most common sleep complaint in the general population. We sought to investigate the association between sleep quality and insomnia and BP nondipping cross-sectionally and longitudinally in a large, community-based sample. METHODS: A subset of the Wisconsin Sleep Cohort (n = 502 for cross-sectional analysis and n = 260 for longitudinal analysis) were enrolled in the analysis. Polysomnography measures were used to evaluate sleep quality. Insomnia symptoms were obtained by questionnaire. BP was measured by 24-h ambulatory BP monitoring. Logistic regression models estimated cross-sectional associations of sleep quality and insomnia with BP nondipping. Poisson regression models estimated longitudinal associations between sleep quality and incident nondipping over a mean 7.4 years of follow-up. Systolic and diastolic nondipping were examined separately. RESULTS: In cross-sectional analyses, difficulty falling asleep, longer waking after sleep onset, shorter and longer total sleep time, lower sleep efficiency and lower rapid eye movement stage sleep were associated with higher risk of SBP and DBP nondipping. In longitudinal analyses, the adjusted relative risks (95% confidence interval) of incident systolic nondipping were 2.1 (1.3-3.5) for 1-h longer waking after sleep onset, 2.1 (1.1-5.1) for 7-8 h total sleep time, and 3.7 (1.3-10.7) for at least 8-h total sleep time (compared with total sleep time 6-7 h), and 1.9 (1.1-3.4) for sleep efficiency less than 0.8, respectively. CONCLUSION: Clinical features of insomnia and poor sleep quality are associated with nondipping BP. Our findings suggested nondipping might be one possible mechanism by which poor sleep quality was associated with worse cardiovascular outcomes.

One-year changes in self-reported napping behaviors across the retirement transition.

OBJECTIVE: To estimate associations of retirement with self-reported frequency and duration of naps. DESIGN: Prospective cohort study. SETTING: Population-based. PARTICIPANTS: 1359 current and former Wisconsin state employees, aged 54-69. MEASUREMENTS: Four annual surveys mailed between 2010 and 2014 elicited employment status and nap characteristics. Changes in employment status and nap characteristics were identified from survey pairs measured 1 year apart (up to 3 survey pairs per subject). General linear mixed models with repeated measures were used to estimate changes in minutes napped per week (MNPW), weekly nap frequency, and individual nap duration as predicted by retirement transitions vs stable employment status. All models were adjusted for demographic characteristics, self-rated health, medical diagnoses, sleep problems, circadian preference, and change in nocturnal sleep duration. RESULTS: There were 3101 survey pairs in the analytic sample. Full retirement (transition from working ≥35 h/wk to not working for pay) over a 1-year period predicted a statistically significantly larger mean change in MNPW than stable employment status: mean (95% confidence interval) = +48 (+16, +80) MNPW. Associations between staged retirement transitions (from full-time to part-time work, or from part-time work to full retirement) and 1-year changes in MNPW were not statistically significant. The MNPW changes associated with full retirement were attributable to nap frequency increase of +0.4 (+0.1, +0.8) d/wk; nap duration did not change significantly. CONCLUSIONS: Compared with stable employment status, full retirement is associated with an average 1-year increase of +48 MNPW. This change is attributable to a frequency gain of 0.4 d/wk napped. Changes in nap duration were negligible.

Subjective sleep measurement: comparing sleep diary to questionnaire.

PURPOSE: The sleep diary is the gold standard of self-reported sleep duration, but its comparability to sleep questionnaires is uncertain. The purpose of this study was to compare self-reported sleep duration between a sleep diary and a sleep questionnaire and to test whether sleep-related disorders were associated with diary-questionnaire differences in sleep duration. PARTICIPANTS AND METHODS: We compared self-reported sleep duration from 5,432 questionnaire-sleep diary pairs in a longitudinal cohort of 1,516 adults. Participants reported sleep information in seven-day sleep diaries and in questionnaires. Research staff abstracted average sleep durations for three time periods (overall; weekday; weekend) from diaries and questionnaires. For each time period, we evaluated diary-questionnaire differences in sleep duration with Welch's two-sample t-tests. Using linear mixed effects regression, we regressed overall diary-questionnaire sleep duration difference on several participant characteristics: reporting any insomnia symptoms, having sleep apnea, sex, body mass index, smoking status, Short Form-12 Physical Health Composite Score, and Short Form-12 Mental Health Composite Score. RESULTS: The average diary-reported overall sleep duration (7.76 hrs) was longer than that of the questionnaire (7.07 hrs) by approximately 41 mins (0.69 hrs, 95% confidence interval: 0.62, 0.76 hrs). Results were consistent across weekday- and weekend-specific differences. Demographic-adjusted linear mixed effects models tested whether insomnia symptoms or sleep apnea were associated with diary-questionnaire differences in sleep duration. Insomnia symptoms were associated with a 17 min longer duration on the diary relative to the questionnaire (ß=0.28 hrs, 95% confidence interval: 0.22, 0.33 hrs), but sleep apnea was not significantly associated with diary-questionnaire difference. Female sex was associated with greater diary-questionnaire duration differences, whereas better self-reported health was associated with lesser differences. CONCLUSION: Diaries and questionnaires are somewhat disparate methods of assessing subjective sleep duration, although diaries report longer duration relative to questionnaires, and insomnia symptoms may contribute to greater perceived differences.