0168 Effects of School Night Sleep Duration and Circadian Preference on Student Tardiness: An Investigation in a Middle-School Aged Sample

Introduction

Sleep and circadian factors play an important role in school attendance, academic performance, and daytime behaviors among adolescents. This investigation assessed school night sleep duration (SNSD) and circadian preference (CP) association with first period tardies (FPT) using a middle-aged sample from the Madison (Wisconsin) Metropolitan School District (MMSD), prior to implementation of a planned district-wide delay in middle school start times.

Methods

4,175 middle-school aged students from 12 MMSD schools completed a sleep survey, which included SNSD and a validated 4-level measure of CP. Self-reported SNSD between 4-and-12 hours served as final sample inclusion criterion. Mixed effects modeling was employed with students nested within school. Linear regression determined SNSD and CP effect on student tardiness. Individual, year-long FPT served as outcome variable. Inclusion of SNSD quadratic term was not statistically indicated. Full model covariates included age, sex, race, parent educational level, homelessness, free and reduced lunch, and special education status.

Results

Final sample included 3,860 students. Univariate regression determined a significant CP association with FPT [β=1.20, 95% CI (0.54, 1.86), F(1,10.41)=13.7, p=0.004), but not SNSD [β=-0.31, 95% CI (-0.70, -0.09), F(1,10.21)=2.5, p=0.14]. SNSD and CP interaction was not significant. CP significance was maintained in the full model [β=1.24, 95% CI (-0.70, -0.09), F(1,11.21)=13.7, p=0.004]. Evening preference associated with 3.72 more FPT, relative to morning preference.

Conclusion

Results suggest evening preference is associated with increased risk of tardiness among middle school students. Future research that examines the relationships between delayed school start times, circadian preference, and impact on school tardiness is indicated.

Support

This research was generously supported by a grant from the Madison Education Partnership (MEP).

0833 Midlife Sleep Health is Associated With Later-Life Depression and Anxiety

Introduction

Several aspects of sleep - collectively conceptualized as ‘sleep health’ - are associated with anxiety and depression. This study investigated whether specific components of sleep health experienced during midlife are associated with depression and anxiety symptoms in later life.

Methods

A subset of Wisconsin Sleep Cohort participants (n=616; 45% female; mean [SD] baseline age=55 [8] years) completed 4 study visits at 4-year intervals. Visits included polysomnography and questionnaires about sleep, mood, and health. Outcomes (Zung depression score, State and Trait Anxiety) were regressed on sleep health characteristics (AHI, %N3 sleep, %REM sleep, sleep efficiency, sleep latency, sleep duration, sleep debt, nap duration, insomnia symptoms, circadian preference, excessive daytime sleepiness [EDS], Epworth Sleepiness Scale [ESS]) using 2 types of linear models adjusting for age, sex, BMI, education, exercise, smoking, and caffeine consumption: 1) longitudinal models in which baseline sleep health predicted mood outcomes 12 years later (adjusting for baseline levels of the outcome variable), and 2) models in which 12-year change in sleep health predicted 12-year change in outcomes.

Results

Longer nap duration, evening circadian preference, and EDS during midlife were associated with worse depression scores in later life. 12-year increases in nap duration, EDS, and ESS were associated with 12-year worsening of depression. Longer sleep duration and greater EDS during midlife were associated with worse trait anxiety in later life. 12-year increases in sleep duration, nap duration, insomnia symptoms, EDS and ESS were associated with 12-year worsening of trait anxiety. Greater AHI and EDS during midlife were associated with worse state anxiety in later life. 12-year increases in ESS were associated with worsening state anxiety. (P<0.05 for all reported results.)

Conclusion

Multiple aspects of sleep health experienced during midlife are associated with greater depression and anxiety in later life.

Support

NIH grants: National Institutes of Aging (R01AG058680; R01AG036838); National Heart, Lung, and Blood Institute (R01HL62252); National Center for Research Resources (1UL1RR025011)

0347 Aging and Retirement are Independently Associated with Reduced Social Jetlag

Introduction

Social jetlag (SJL; difference in sleep timing on freedays versus workdays) is a measure of chronic circadian misalignment due to a mismatch between preferred biological sleep timing and societal scheduling demands. Cross-sectionally, greater SJL is associated with poorer health and younger age. We assessed longitudinal changes in SJL across aging and retirement.

Methods

In 1137 participants of the Wisconsin Sleep Cohort (WSC), sleep timing was collected via sleep diaries every 4 years (2802 data points, 47% female, mean age 51 years at baseline (+/-8 SD, range 31 - 74)). In 829 participants of the Retirement and Sleep Trajectories study (REST, an ancillary study of the WSC), sleep timing and retirement status were collected in 4 annual mailed surveys (1700 data points, 55% female, mean age 59 years at baseline (range 46-81)). Midsleep was defined as the time midway between bedtime and waketime. SJL was defined as the absolute difference between midsleep on workdays/weekdays and freedays/weekends. Mixed models were used to test associations of change in sleep timing with change in age, retirement status and self-reported health.

Results

In the WSC, aging 10 years was associated with 16 minutes reduction in SJL (p<.001), driven by a shift of midsleep to 7 minutes later on weekdays and 10 minutes earlier on weekends. The effect of age on SJL remained significant when tested only in employed people. In the REST study, the transition from full time employment to full time retirement was associated with ~ 1 hour shorter SJL, maintained 1, 2 and 3 years post-transition (p<.001, controlling for age). Greater SJL was associated with worse self-rated health (p=.02).

Conclusion

Aging and the transition from employment to retirement are independently associated with reduced social jetlag. Greater social jetlag is associated with poorer self-reported health.

Support

This study was supported by grants from the National Institutes of Health (NIH): R01HL62252, R01AG036838, R01AG058680, and 1UL1RR02501.

0048 The Association Between REM Sleep and Risk of Mortality in Three Independent Cohorts

Introduction

Sleep disorders and sleep characteristics have been linked to higher risk of mortality. Despite the emerging evidence of a sleep-mortality association, the relationship between sleep architecture and mortality aren’t well understood. We hypothesize that reduced REM is associated with increased mortality risk.

Methods

The Osteoporotic Fractures in Men (MrOS) study is a population-based study of 2,675 older men. Cox regression was used to evaluate the association between %REM and mortality rate. Potential covariates were evaluated using 6-fold cross validation. Sensitivity analyses were performed to rule out alternative explanations. Wisconsin Sleep Cohort (WSC) and Sleep Heart Health Study (SHHS) data were used to replicate the findings.

Results

The MrOS sample mean age was 76.3 years (SD=5.51) and the median follow-up time was 12.1 years. There was a 13% higher rate of mortality for every absolute 5% reduction in REM sleep (HR=1.13, 95%CI, 1.08–1.19) after adjusting for multiple demographic, sleep, and health covariates. The association persisted for cardiovascular disease-related mortality (CVD) (HR=1.18, 95%CI, 1.09–1.28), cancer-related mortality (HR=1.14, 95%CI, 1.03–1.26), and other mortality (HR=1.19, 95%CI, 1.10–1.28). The WSC included 45.7% women. The mean age of the 1,388 individuals analyzed was 51.5 (SD=8.5); the median follow-up time was 20.8 years. The effect size for 5% reduction in REM on rate of all-cause mortality was similar in this cohort despite the younger age, inclusion of women, and longer follow-up period (HR=1.17, 95%CI, 1.03–1.34). SHHS data is still being analyzed; however the unadjusted model is consistent with the other cohorts.

Conclusion

We found an association between reduced REM and mortality in two, possibly three independent cohorts, which persisted across different causes of death and multiple sensitivity analyses. Mechanistic studies are needed and strategies to preserve REM may influence clinical therapies and reduce mortality risk.

Support

NHLBI provides funding for the MrOS Sleep ancillary study “Outcomes of Sleep Disorders in Older Men” under grant numbers: R01 HL071194, R01 HL070848, R01 HL070847, R01 HL070842, R01 HL070841, R01 HL070837, R01 HL070838, and R01 HL070839. Wisconsin Sleep Cohort was supported by R01HL62252, RR03186, and R01AG14124 from the NIH. Dr. Redline was partially supported by NHLBI R35 HL135818.

0267 School Night Sleep Duration Effect on Risk for In-and-Out of School Suspensions: An Investigation in a Middle-School Aged Sample

Introduction

Sleep plays an important role in adolescent education and development. Sleep impacts student school attendance, academic performance, and daytime behaviors. There has been limited investigation into the impact on sleep duration (SD) on school suspension risk. Given the growing public health and policy focus on altering school start times to increase SD, this study assessed SD association with school suspension risk using a middle-school aged sample from the Madison (Wisconsin) Metropolitan School District (MMSD), prior to implementation of a planned district-wide delay in middle school start times.

Methods

4,175 middle-school aged students from 12 MMSD schools completed a sleep survey, which included school-night SD (SNSD). Self-reported SNSD between 4-and-12 hours served as criterion for inclusion in final sample. Mixed effects modeling was employed with students nested within school. Logistic regression determined SNSD association with in-school (ISS) and out-of-school (OSS) suspensions. ISS and OSS were dichotomized (No ISS/OSS = 0; nonzero ISS/OSS = 1) to serve as outcome variables. Full model covariates included age, sex, race, circadian preference, parent educational level, homelessness, free and reduced lunch, and special education status.

Results

Final sample included 3,860 students. Shorter SNSD associated with greater likelihood of OSS [OR = 0.83, 95% CI (-0.28, -0.09), X2 = 16.1, p < 0.0001], but not ISS [OR = 0.97, 95% CI (-0.14, -0.070), X2 = 0.44, p = 0.51]. Significance between SNSD and OSS was maintained in the full model [OR = 0.84, 95% CI (-0.27, -0.08), X2 = 13.2, p = 0.0003]. Each additional hour of sleep associated with 16% lower risk of OSS.

Conclusion

These results suggest that students with shorter SD are at increased risk for OSS, which further highlights the potential deleterious impact of short SD on adolescent educational experience.

Support

This research was generously supported by a grant from the Madison Education Partnership (MEP).

A method to guide community planning and evaluation efforts in tobacco control using data on smoking during pregnancy

BACKGROUND

Effective community based tobacco control programmes are critical for state and nationwide impact. However, there is little discussion in the literature of methods for setting local objectives which use locally collected data and account for historical variation in progress.

OBJECTIVES

To develop and illustrate a method that uses locally available birth certificate data to model trends in tobacco use during pregnancy among women giving birth, predict future prevalence, and use predictions to set community specific tobacco control objectives.

DATA SOURCE

Vital statistics. Wisconsin standard birth certificates, 1990-2000, which record the smoking status of the mother during pregnancy.

DATA ANALYSIS

Trends in the prevalence of smoking during pregnancy in Wisconsin statewide and in all counties (n = 72) were modelled using linear regression of log prevalence on year. Model fit was assessed using R(2). Regression slopes, indicating estimated relative annual percentage change in prevalence, were used to predict prevalence in 2005, and objectives were calculated as a 20% reduction from the predicted prevalence in 2005.

CONCLUSIONS

Modelling trends in the prevalence of smoking using locally collected data enables communities to set reasonable future tobacco control objectives that account for historical trends in progress.

Association between apolipoprotein E epsilon4 and sleep-disordered breathing in adults

CONTEXT

Apolipoprotein E epsilon4(ApoE epsilon4) is a well-known risk factor for Alzheimer disease and cardiovascular disease. Sleep-disordered breathing occurs in Alzheimer disease patients and increases risks for cardiovascular disease. Complex interactions among sleep, brain pathology, and cardiovascular disease may occur in ApoE epsilon4 carriers.

OBJECTIVE

To study whether genetic variation at the level of ApoE is associated with sleep-disordered breathing or sleep abnormalities in the general population.

DESIGN, SETTING, AND PARTICIPANTS

Ongoing longitudinal cohort study of sleep disorders at a US university beginning in 1989, providing a population-based probability sample of 791 middle-aged adults (mean [SD] age, 49 [8] years; range, 32-68 years).

MAIN OUTCOME MEASURE

Nocturnal polysomnography to evaluate apnea-hypopnea index.

RESULTS

The probability of moderate-to-severe sleep-disordered breathing (apnea-hypopnea index >/=15%) was significantly higher in participants with epsilon4, independent of age, sex, body mass index, and ethnicity (12.0% vs 7.0%; P =.003). Mean (SEM) apnea-hypopnea index was also significantly higher in participants with ApoE epsilon4 (6.5 [0.6] vs 4.8 [0.3]; P =.01). These effects increased with the number of ApoE epsilon4 alleles carried.

CONCLUSIONS

A significant portion of sleep-disordered breathing is associated with ApoE epsilon4 in the general population.

Longitudinal study of moderate weight change and sleep-disordered breathing

CONTEXT

Excess body weight is positively associated with sleep-disordered breathing (SDB), a prevalent condition in the US general population. No large study has been conducted of the longitudinal association between SDB and change in weight.

OBJECTIVE

To measure the independent longitudinal association between weight change and change in SDB severity.

DESIGN

Population-based, prospective cohort study conducted from July 1989 to January 2000.

SETTING AND PARTICIPANTS

Six hundred ninety randomly selected employed Wisconsin residents (mean age at baseline, 46 years; 56% male) who were evaluated twice at 4-year intervals for SDB.

MAIN OUTCOME MEASURES

Percentage change in the apnea-hypopnea index (AHI; apnea events + hypopnea events per hour of sleep) and odds of developing moderate-to-severe SDB (defined by an AHI > or =15 events per hour of sleep), with respect to change in weight.

RESULTS

Relative to stable weight, a 10% weight gain predicted an approximate 32% (95% confidence interval [CI], 20%-45%) increase in the AHI. A 10% weight loss predicted a 26% (95% CI, 18%-34%) decrease in the AHI. A 10% increase in weight predicted a 6-fold (95% CI, 2.2-17.0) increase in the odds of developing moderate-to-severe SDB.

CONCLUSIONS

Our data indicate that clinical and public health programs that result in even modest weight control are likely to be effective in managing SDB and reducing new occurrence of SDB.

Sleep fragmentation, awake blood pressure, and sleep-disordered breathing in a population-based study

Arousal from sleep produces transient increases in systemic blood pressure, leading to the suggestion that repeated arousals are associated with a sustained increase in daytime blood pressure. Using data from the Wisconsin Sleep Cohort Study, a population-based study, we tested the hypothesis that sleep fragmentation is associated with elevated awake blood pressure. Sleep, breathing, and seated blood pressure measurements from 1,021 participants (age 42 +/- 8 yr; 590 males) were analyzed. Sleep fragmentation was defined as the total number of awakenings and shifts to Stage 1 sleep divided by the total sleep time (sleep fragmentation index: SFI). To reduce the confounding influence of sleep-disordered breathing, which is related to both increased daytime blood pressure and sleep fragmentation, all participants with an apnea-hypopnea index (AHI) > or = 1 were analyzed separately. Accounting for the influences of sex, age, body mass index, and antihypertensive medication use, the SFI was significantly associated with higher levels of awake systolic blood pressure in people with an AHI < 1; a 2 standard deviation increase in the SFI was associated with a 3.1 mm Hg rise in awake systolic blood pressure. In participants with an AHI > or = 1, there was no independent association between the SFI and awake blood pressure after controlling for the influence of the AHI.

Prospective study of the association between sleep-disordered breathing and hypertension

BACKGROUND

Sleep-disordered breathing is prevalent in the general population and has been linked to chronically elevated blood pressure in cross-sectional epidemiologic studies. We performed a prospective, population-based study of the association between objectively measured sleep-disordered breathing and hypertension (defined as a laboratory-measured blood pressure of at least 140/90 mm Hg or the use of antihypertensive medications).

METHODS

We analyzed data on sleep-disordered breathing, blood pressure, habitus, and health history at base line and after four years of follow-up in 709 participants of the Wisconsin Sleep Cohort Study (and after eight years of follow-up in the case of 184 of these participants). Participants were assessed overnight by 18-channel polysomnography for sleep-disordered breathing, as defined by the apnea-hypopnea index (the number of episodes of apnea and hypopnea per hour of sleep). The odds ratios for the presence of hypertension at the four-year follow-up study according to the apnea-hypopnea index at base line were estimated after adjustment for base-line hypertension status, body-mass index, neck and waist circumference, age, sex, and weekly use of alcohol and cigarettes.

RESULTS

Relative to the reference category of an apnea-hypopnea index of 0 events per hour at base line, the odds ratios for the presence of hypertension at follow-up were 1.42 (95 percent confidence interval, 1.13 to 1.78) with an apnea-hypopnea index of 0.1 to 4.9 events per hour at base line as compared with none, 2.03 (95 percent confidence interval, 1.29 to 3.17) with an apnea-hypopnea index of 5.0 to 14.9 events per hour, and 2.89 (95 percent confidence interval, 1.46 to 5.64) with an apnea-hypopnea index of 15.0 or more events per hour.

CONCLUSIONS

We found a dose-response association between sleep-disordered breathing at base line and the presence of hypertension four years later that was independent of known confounding factors. The findings suggest that sleep-disordered breathing is likely to be a risk factor for hypertension and consequent cardiovascular morbidity in the general population.