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.

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.

Multiethnic Meta-Analysis Identifies RAI1 as a Possible Obstructive Sleep Apnea-related Quantitative Trait Locus in Men.

Obstructive sleep apnea (OSA) is a common heritable disorder displaying marked sexual dimorphism in disease prevalence and progression. Previous genetic association studies have identified a few genetic loci associated with OSA and related quantitative traits, but they have only focused on single ethnic groups, and a large proportion of the heritability remains unexplained. The apnea-hypopnea index (AHI) is a commonly used quantitative measure characterizing OSA severity. Because OSA differs by sex, and the pathophysiology of obstructive events differ in rapid eye movement (REM) and non-REM (NREM) sleep, we hypothesized that additional genetic association signals would be identified by analyzing the NREM/REM-specific AHI and by conducting sex-specific analyses in multiethnic samples. We performed genome-wide association tests for up to 19,733 participants of African, Asian, European, and Hispanic/Latino American ancestry in 7 studies. We identified rs12936587 on chromosome 17 as a possible quantitative trait locus for NREM AHI in men (N = 6,737; P = 1.7 × 10-8) but not in women (P = 0.77). The association with NREM AHI was replicated in a physiological research study (N = 67; P = 0.047). This locus overlapping the RAI1 gene and encompassing genes PEMT1, SREBF1, and RASD1 was previously reported to be associated with coronary artery disease, lipid metabolism, and implicated in Potocki-Lupski syndrome and Smith-Magenis syndrome, which are characterized by abnormal sleep phenotypes. We also identified gene-by-sex interactions in suggestive association regions, suggesting that genetic variants for AHI appear to vary by sex, consistent with the clinical observations of strong sexual dimorphism.

Sleep-spindle detection: crowdsourcing and evaluating performance of experts, non-experts and automated methods.

Sleep spindles are discrete, intermittent patterns of brain activity observed in human electroencephalographic data. Increasingly, these oscillations are of biological and clinical interest because of their role in development, learning and neurological disorders. We used an Internet interface to crowdsource spindle identification by human experts and non-experts, and we compared their performance with that of automated detection algorithms in data from middle- to older-aged subjects from the general population. We also refined methods for forming group consensus and evaluating the performance of event detectors in physiological data such as electroencephalographic recordings from polysomnography. Compared to the expert group consensus gold standard, the highest performance was by individual experts and the non-expert group consensus, followed by automated spindle detectors. This analysis showed that crowdsourcing the scoring of sleep data is an efficient method to collect large data sets, even for difficult tasks such as spindle identification. Further refinements to spindle detection algorithms are needed for middle- to older-aged subjects.

Relationships between sleep apnea, cardiovascular disease risk factors, and aortic pulse wave velocity over 18 years: the Wisconsin Sleep Cohort.

PURPOSE: The purpose of this study is to determine if apnea-hypopnea index (AHI) severity predicts future aortic pulse wave velocity (PWV) in the Wisconsin Sleep Cohort. METHODS: Applanation tonometry was used to derive carotid-to-femoral PWV a mean of 18 years (standard deviation 4) after overnight polysomnography. Multivariable regression models were created to describe prospective associations between baseline AHI and future PWV. RESULTS: The 618 adults were mean 65 (7) years old (55 % male) with a mean body mass index of 31 (7) kg/m(2) at the tonometry visit. Mean baseline AHI was 4.6 (9.7) events/h. In multiple linear regression models adjusted for age (ß = 0.13/year, standard error [SE] = 0.01, p < 0.001) and sex, higher log10AHI (ß = 0.43/events/h, SE = 0.18, p = 0.02) was associated with PWV. After adjustment for waist circumference (ß = 0.01/cm, SE = 0.01, p = 0.05) and height, the association between baseline log10AHI and future PWV was not statistically significant (p = 0.11), although the association with age persisted unchanged. Addition of covariates such as smoking status (current smoker ß = 0.66, SE = 0.22, p = 0.002), diabetes mellitus status (ß = 2.89, SE = 0.59, p < 0.001), and systolic blood pressure (BP, ß = 0.03/mmHg, SE = 0.01, p < 0.001) did not change the association. AHI did not interact with age or smoking status to predict PWV. A secondary analysis of nocturnal oxygen saturation parameters in 517 participants, 9 (2) years prior also did not show any significant relationships with future PWV. CONCLUSIONS: The prospective association between AHI and PWV is confounded by body size and influenced by smoking, diabetes mellitus, and BP. Weight management, BP control, and smoking cessation may help prevent arterial stiffening associated with obstructive sleep apnea.

Obstructive sleep apnoea during REM sleep and incident non-dipping of nocturnal blood pressure: a longitudinal analysis of the Wisconsin Sleep Cohort.

BACKGROUND: Non-dipping of nocturnal blood pressure (BP) is associated with target organ damage and cardiovascular disease. Obstructive sleep apnoea (OSA) is associated with incident non-dipping. However, the relationship between disordered breathing during rapid eye movement (REM) sleep and the risk of developing non-dipping has not been examined. This study investigates whether OSA during REM sleep is associated with incident non-dipping. METHODS: Our sample included 269 adults enrolled in the Wisconsin Sleep Cohort Study who completed two or more 24 h ambulatory BP studies over an average of 6.6 years of follow-up. After excluding participants with prevalent non-dipping BP or antihypertensive use at baseline, there were 199 and 215 participants available for longitudinal analysis of systolic and diastolic non-dipping, respectively. OSA in REM and non-REM sleep were defined by apnoea hypopnoea index (AHI) from baseline in-laboratory polysomnograms. Systolic and diastolic non-dipping were defined by systolic and diastolic sleep/wake BP ratios >0.9. Modified Poisson regression models estimated the relative risks for the relationship between REM AHI and incident non-dipping, adjusting for non-REM AHI and other covariates. RESULTS: There was a dose-response greater risk of developing systolic and diastolic non-dipping BP with greater severity of OSA in REM sleep (p-trend=0.021 for systolic and 0.024 for diastolic non-dipping). Relative to those with REM AHI<1 event/h, those with REM AHI≥15 had higher relative risk of incident systolic non-dipping (2.84, 95% CI 1.10 to 7.29) and incident diastolic non-dipping (4.27, 95% CI 1.20 to 15.13). CONCLUSIONS: Our findings indicate that in a population-based sample, REM OSA is independently associated with incident non-dipping of BP.

Cumulative exposure to short sleep and body mass outcomes: a prospective study.

Short sleep duration is associated with excess body mass among adolescents and young adults. The mechanisms theorized to drive that association suggest that persistent exposure to short sleep should be associated with greater accumulations of body mass. We use prospective cohort data from four waves of the National Longitudinal Study of Adolescent to Adult Health (1994-2009; n = 14 800) to examine associations between cumulative exposure to short sleep throughout adolescence and early adulthood and obesity and elevated waist circumference outcomes. We compare several clinical and distribution-based standards of short sleep to assess which measures are associated most strongly with body mass. Cumulative exposure to short sleep exhibits dose-response associations with obesity and elevated waist circumference. Relative to respondents with no instances of short sleep, those who slept -0.50 standard deviations or less than the age and sex-specific average sleep hours in all four waves had 1.45 [95% confidence interval (CI): 1.03, 2.04] times the odds of being obese and 1.45 (95% CI: 1.02, 2.06) times the odds of having an elevated waist circumference. Our findings suggest that cumulative exposure to short sleep during adolescence and young adulthood may play an important role in the etiology of obesity and elevated waist circumference during this important developmental period.

Minimal nocturnal oxygen saturation predicts future subclinical carotid atherosclerosis: the Wisconsin sleep cohort.

Previous data on the associations between nocturnal oxygen saturation parameters and carotid atherosclerosis are conflicting. We examined the prospective associations of nocturnal oxygen saturation (SaO2 ) and cardiovascular disease (CVD) risk factors with carotid intima-media thickness (IMT) and plaques. We used data on 689 Wisconsin sleep cohort participants who had baseline overnight polysomnography followed by carotid ultrasonography a mean (SD) of 7.8 (2.5) years later. Far wall common carotid IMT was measured using B-mode ultrasound. Bilateral common, bifurcation and internal carotid artery segments were evaluated for plaque score. Participants (8) were aged 56 years (55% male); 32% had hypertension and mean body mass index (BMI) was 31 (7) kg m(2). Mean and minimum nocturnal SaO2 were 95% (2) and 86% (7), respectively. Mean percentage sleep time with SaO2 < 90% was 2% (8). Both mean (odds ratio [OR]: 0.60 lower plaque count per 5% higher mean SaO2, 95% confidence interval [CI]: 0.38-0.96, P = 0.033) and minimum SaO2 (OR: 0.88 lower plaque count per 5% higher minimum SaO2, 95% CI: 0.80-0.97, P = 0.013) predicted carotid plaque score after adjusting for age, sex and BMI. Minimum SaO2 predicted future plaque score after adding adjustment for traditional CVD risk factors (OR: 0.90 lower plaque count per 5% higher minimum SaO2, 95% CI: 0.81-0.99, P = 0.038). Mean SaO2 was not associated with carotid IMT after CVD risk factor adjustment. We conclude that minimum nocturnal SaO2 is an independent predictor of future carotid plaque burden. Other nocturnal SaO2 parameters are not associated with future carotid IMT or plaques after adjusting for traditional CVD risk factors.

Obstructive sleep apnea is associated with future subclinical carotid artery disease: thirteen-year follow-up from the Wisconsin sleep cohort.

OBJECTIVE: To determine the longitudinal associations between obstructive sleep apnea, carotid artery intima-media thickness (IMT), and plaque. APPROACH AND RESULTS: This is a population-based, prospective cohort study conducted from July, 1989, to November, 2012, on 790 randomly selected Wisconsin residents who completed a mean of 3.5 (range, 1-6) polysomnograms during the study period. Obstructive sleep apnea was characterized by the apnea-hypopnea index (AHI, events/h). Common carotid artery IMT and plaque were assessed by B-mode ultrasound. The mean (SD) time from the first polysomnograms to carotid ultrasound was 13.5 (3.6) years. Multivariable regression models were created to estimate the independent associations of baseline and cumulative obstructive sleep apnea exposure with subsequent carotid IMT and plaque. At baseline, the mean age of participants was 47.6 (7.7) years (55% men, 97% white). AHI was 4.4 (9.0) events/h (range, 0-97); 7% had AHI >15 events/h. Carotid IMT was 0.755 (0.161) mm; 63% had plaque. Adjusting for age, sex, body mass index, systolic blood pressure, smoking, and use of lipid-lowering, antihypertensive, and antidiabetic medications, baseline AHI independently predicted future carotid IMT (ß=0.027 mm/unit log10[AHI+1]; P=0.049), plaque presence (odds ratio, 1.55 [95% confidence intervals, 1.02-2.35]; P=0.041) and plaque score (odds ratio, 1.30 [1.05-1.61]; P=0.018). In cumulative risk factor-adjusted models, AHI independently predicted future carotid plaque presence (P=0.012) and score (P=0.039), but not IMT (P=0.608). CONCLUSIONS: Prevalent obstructive sleep apnea is independently associated with increased carotid IMT and plaque more than a decade later, indicating increased future cardiovascular disease risk.

Obstructive sleep apnea during REM sleep and hypertension. results of the Wisconsin Sleep Cohort.

RATIONALE: Obstructive sleep apnea (OSA) is associated with hypertension. OBJECTIVES: We aimed to quantify the independent association of OSA during REM sleep with prevalent and incident hypertension. METHODS: We included adults enrolled in the longitudinal community-based Wisconsin Sleep Cohort Study with at least 30 minutes of REM sleep obtained from overnight in-laboratory polysomnography. Studies were repeated at 4-year intervals to quantify OSA. Repeated measures logistic regression models were fitted to explore the association between REM sleep OSA and prevalent hypertension in the entire cohort (n = 4,385 sleep studies on 1,451 individuals) and additionally in a subset with ambulatory blood pressure data (n = 1,085 sleep studies on 742 individuals). Conditional logistic regression models were fitted to longitudinally explore the association between REM OSA and development of hypertension. All models controlled for OSA events during non-REM sleep, either by statistical adjustment or by stratification. MEASUREMENTS AND MAIN RESULTS: Fully adjusted models demonstrated significant dose-relationships between REM apnea-hypopnea index (AHI) and prevalent hypertension. The higher relative odds of prevalent hypertension were most evident with REM AHI greater than or equal to 15. In individuals with non-REM AHI less than or equal to 5, a twofold increase in REM AHI was associated with 24% higher odds of hypertension (odds ratio, 1.24; 95% confidence interval, 1.08-1.41). Longitudinal analysis revealed a significant association between REM AHI categories and the development of hypertension (P trend = 0.017). Non-REM AHI was not a significant predictor of hypertension in any of the models. CONCLUSIONS: Our findings indicate that REM OSA is cross-sectionally and longitudinally associated with hypertension. This is clinically relevant because treatment of OSA is often limited to the first half of the sleep period leaving most of REM sleep untreated.

Association between asthma and risk of developing obstructive sleep apnea.

IMPORTANCE: Obstructive sleep apnea (OSA) is more common among patients with asthma; whether asthma is associated with the development of OSA is unknown. OBJECTIVE: To examine the prospective relationship of asthma with incident OSA. DESIGN, SETTING, AND PARTICIPANTS: Population-based prospective epidemiologic study (the Wisconsin Sleep Cohort Study) beginning in 1988. Adult participants were recruited from a random sample of Wisconsin state employees to attend overnight polysomnography studies at 4-year intervals. Asthma and covariate information were assessed during polysomnography studies through March 2013. Eligible participants were identified as free of OSA (apnea-hypopnea index [AHI] of <5 events/h and not treated) by 2 baseline polysomnography studies. There were 1105 4-year follow-up intervals provided by 547 participants (52% women; mean [SD] baseline age, 50 [8] years). EXPOSURES: Questionnaire-assessed presence and duration of self-reported physician-diagnosed asthma. MAIN OUTCOMES AND MEASURES: The associations of presence and duration of asthma with 4-year incidences of both OSA (AHI of ≥5 or positive airway pressure treatment) and OSA concomitant with habitual daytime sleepiness were estimated using repeated-measures Poisson regression, adjusting for confounders. RESULTS: Twenty-two of 81 participants (27% [95% CI, 17%-37%]) with asthma experienced incident OSA over their first observed 4-year follow-up interval compared with 75 of 466 participants (16% [95% CI, 13%-19%]) without asthma. Using all 4-year intervals, participants with asthma experienced 45 cases of incident OSA during 167 4-year intervals (27% [95% CI, 20%-34%]) and participants without asthma experienced 160 cases of incident OSA during 938 4-year intervals (17% [95% CI, 15%-19%]); the corresponding adjusted relative risk (RR) was 1.39 (95% CI, 1.06-1.82), controlling for sex, age, baseline and change in body mass index, and other factors. Asthma was also associated with new-onset OSA with habitual sleepiness (RR, 2.72 [95% CI, 1.26-5.89], P = .045). Asthma duration was related to both incident OSA (RR, 1.07 per 5-year increment in asthma duration [95% CI, 1.02-1.13], P = .01) and incident OSA with habitual sleepiness (RR, 1.18 [95% CI, 1.07-1.31], P = .02). CONCLUSIONS AND RELEVANCE: Asthma was associated with an increased risk of new-onset OSA. Studies investigating the mechanisms underlying this association and the value of periodic OSA evaluation in patients with asthma are warranted.

Do sleep-deprived adolescents make less-healthy food choices?

Short sleep duration among children and adolescents has been reported to be associated with elevated BMI and other adverse health outcomes. Food choices are one proposed mechanism through which this association may occur. In the present study, we examined whether self-reported habitual sleep duration is associated with vegetable and fruit consumption and fast food consumption. Using cross-sectional data from the National Longitudinal Study of Adolescent Health (n 13,284), we estimated three nested logistic regression models for two outcome variables: daily vegetable and fruit consumption and previous week's fast food consumption. The adjusted models included demographic and social/behavioural covariates. Self-reported habitual short sleep duration ( < 7 h/night) was associated with reduced odds of vegetable and fruit consumption compared with the recommended sleep duration (>8 h/night) (OR 0·66, P <0·001), even after adjusting for demographic and social/behavioural factors (OR 0·75, P <0·001). Short sleep duration was also associated with increased odds of fast food consumption (OR 1·40, P <0·001) even after adjustment (OR 1·20, P <0·05). Food choices are significantly associated with sleep duration and may play an important role in the mediation of the association between sleep and health among adolescents.

The Wisconsin Assessment of the Social and Built Environment (WASABE): a multi-dimensional objective audit instrument for examining neighborhood effects on health.

BACKGROUND: Growing evidence suggests that mixed methods approaches to measuring neighborhood effects on health are needed. The Wisconsin Assessment of the Social and Built Environment (WASABE) is an objective audit tool designed as an addition to a statewide household-based health examination survey, the Survey of the Health of Wisconsin (SHOW), to objectively measure participant's neighborhoods. METHODS: This paper describes the development and implementation of the WASABE and examines the instrument's ability to capture a range of social and built environment features in urban and rural communities. A systematic literature review and formative research were used to create the tool. Inter-rater reliability parameters across items were calculated. Prevalence and density of features were estimated for strata formed according to several sociodemographic and urbanicity factors. RESULTS: The tool is highly reliable with over 81% of 115 derived items having percent agreement above 95%. It captured variance in neighborhood features in for a diverse sample of SHOW participants. Sidewalk density in neighborhoods surrounding households of participants living at less than 100% of the poverty level was 67% (95% confidence interval, 55-80%) compared to 34% (25-44%) for those living at greater than 400% of the poverty level. Walking and biking trails were present in 29% (19-39%) of participant buffer in urban areas compared to only 7% (2-12%) in rural communities. Significant environmental differences were also observed for white versus non-white, high versus low income, and college graduates versus individuals with lower level of education. CONCLUSIONS: The WASABE has strong inter-rater reliability and validity properties. It builds on previous work to provide a rigorous and standardized method for systematically gathering objective built and social environmental data in a number of geographic settings. Findings illustrate the complex milieu of built environment features found in participants neighborhoods and have relevance for future research, policy, and community engagement purposes.

Genome-wide association study identifies novel restless legs syndrome susceptibility loci on 2p14 and 16q12.1.

Restless legs syndrome (RLS) is a sensorimotor disorder with an age-dependent prevalence of up to 10% in the general population above 65 years of age. Affected individuals suffer from uncomfortable sensations and an urge to move in the lower limbs that occurs mainly in resting situations during the evening or at night. Moving the legs or walking leads to an improvement of symptoms. Concomitantly, patients report sleep disturbances with consequences such as reduced daytime functioning. We conducted a genome-wide association study (GWA) for RLS in 922 cases and 1,526 controls (using 301,406 SNPs) followed by a replication of 76 candidate SNPs in 3,935 cases and 5,754 controls, all of European ancestry. Herein, we identified six RLS susceptibility loci of genome-wide significance, two of them novel: an intergenic region on chromosome 2p14 (rs6747972, P = 9.03 × 10(-11), OR = 1.23) and a locus on 16q12.1 (rs3104767, P = 9.4 × 10(-19), OR = 1.35) in a linkage disequilibrium block of 140 kb containing the 5'-end of TOX3 and the adjacent non-coding RNA BC034767.

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.

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.