Associations of actigraph sleep characteristics with blood pressure among older adults.

OBJECTIVES: Many studies have examined links between sleep and blood pressure, with mixed findings, mostly using self-reported sleep data and cross-sectional designs. We examined whether actigraph-estimated sleep characteristics are associated with concurrent blood pressure or 5-year blood pressure change in a national cohort of older adults (National Social Life, Health and Aging Project), and whether these associations differ by hypertension medication use. METHODS: Subjects were 669 older adults (62-90years), 471 with 5-year follow-up data. Sleep characteristics were duration (linear plus quadratic terms); sleep percentage; and categorical onset, midpoint, and waking times. Multivariable linear models adjusted for age, race, gender, obesity, smoking, daytime napping, and hypertension medication use. Interactions between sleep characteristics and hypertension medication were tested among the 401 subjects with consistent hypertension medication status over time. RESULTS: We found U-shaped cross-sectional and longitudinal relationships between duration and blood pressure, with shorter and longer sleep times associated with higher blood pressure. Later onset times were cross-sectionally associated with higher systolic blood pressure, while earlier onset times were longitudinally associated with systolic blood pressure increase. Midpoint, wake time, and sleep percentage were not significantly associated with blood pressure. Significant interaction terms suggested hypertension medications attenuated associations of sleep onset and wake time with diastolic blood pressure. CONCLUSIONS: These results with actigraph-estimated parameters confirm some, but not all, associations reported from research based on self-reported sleep data. Our findings are consistent with recommended intermediate sleep durations for cardiovascular health and suggest hypertension medication may attenuate some associations between sleep timing and blood pressure.

Risk Factors for Hospital Readmission in Patients With Interstitial Lung Disease.

BACKGROUND: Little is known about the rates, causes, or risk factors for hospital readmission among patients with interstitial lung disease (ILD). We investigated the prevalence, features, and comorbidities of subjects hospitalized with ILD and their subsequent re-hospitalizations in this retrospective study. METHODS: A retrospective analysis of subjects enrolled in the University of Chicago ILD Natural History registry was conducted. Demographic data, comorbidities, and timing and cause of subsequent hospitalizations were collected from the medical record. The primary outcome was time to first readmission via a cause-specific Cox hazards model with a sensitivity analysis with the Fine-Gray cumulative hazard model; the secondary outcome was the number of hospitalizations per subject via a Poisson multivariable model. RESULTS: Among 1,796 patients with ILD, 443 subjects were hospitalized, with 978 total hospitalizations; 535 readmissions were studied, 282 (53%) for a respiratory indication. For the outcome of time to readmission, Black race was the only subject characteristic associated with an increased hazard of readmission in the Cox model (hazard ratio 1.50, P = .03) while Black race, hypersensitivity pneumonitis, and sarcoidosis were associated with increased hazard of readmission in the Fine-Gray model. Black race, female sex, atrial fibrillation, obstructive lung disease, and pulmonary hypertension were associated with an increased number of hospitalizations in the Poisson model. CONCLUSIONS: We demonstrated that hospital readmission from any cause was a common occurrence in subjects with ILD. Further efforts to improve quality of life among these subjects could focus on risk scores for readmission, mitigating racial health disparities, and treatment of comorbidities.

Did Resilience and Socioeconomic Status Predict Older Adults' Finding a Silver Lining in COVID?

Background and Objectives: The coronavirus disease 2019 (COVID-19) pandemic stretched our limits-physically, mentally, and economically. However, some older adults report that it led to positive changes. This study aims to understand whether prepandemic resilience, education, or income predicted older adults' subsequent likelihood of reporting positive changes in their lives during the pandemic. Research Design and Methods: We use data from the National Social Life, Heath, and Aging Project, an ongoing panel study with a COVID-19 ancillary supplement (N = 2,650). Results: The study results aligned with the fundamental cause theory. In demographically adjusted models including resilience, education, and income, as well as the effect of the pandemic on employment and a COVID-disruption score, the odds of reporting any positive change were 2.6 times higher for those with an associate degree (p < .01) and 4.7 times higher for those with a bachelor's or higher (p < .001), compared to those without a high school degree. In contrast, neither resilience nor income was significantly associated with endorsing a positive change. We also categorize specific changes thematically coded from open-ended responses and examine their demographic distributions. Categories include spirituality, home organization, hygiene practices, and increased quality time with others. Discussion and Implications: These findings show that older adults with more education could navigate COVID-19 challenges in a way that improved their perspectives on at least one aspect of their lives.

Stress, Isolation, and Sleep Quality among Breast Cancer Survivors throughout the COVID-19 Pandemic: A Longitudinal Study in a Multi-Ethnic Cohort.

Purpose: This study examined how stress, isolation, and sleep quality were impacted throughout the COVID-19 pandemic among breast cancer survivors (BCS). Methods: BCS enrolled in the Chicago Multiethnic Epidemiologic Breast Cancer Cohort were surveyed in 2020, 2021, and 2022. An 11-item isolation/stress score was repeatedly measured in each survey and its changes were examined through mixed-effects models. Sleep quality was assessed in 2022 by the Insomnia Severity Index (ISI). Results: In total, 1899 BCS responded (response rate: 62.8%), of whom 69% were White and 24% Black (median time since diagnosis: 5.1 years, IQR: 2.3-9.2). The isolation/stress score decreased significantly from 2020 to 2022 for White BCS, but only started declining for Black BCS in 2022. Consequently, although there were no significant racial difference in 2020, Black BCS had significantly higher isolation/stress scores in 2021 and 2022 (P < .01), while it became nonsignificant after adjusting for socioeconomic factors. BCS who were single, on Medicaid, without a high school degree, or with annual household income <$35,000 had significantly higher isolation/stress scores. Regarding sleep quality, 48% of BCS reported clinically-significant insomnia (ISI ≥ 8), and insomnia was strongly associated with higher isolation/stress scores (P-trend < .001). Conclusions: Our findings suggested that the isolation/stress level improved among BCS as the pandemic subsided, but this positive trend was not observed equally across racial/ethnic groups potentially due to lack of resources. Implications for Cancer Survivors: Additional resources, such as access to counseling services and sleep assistance programs, might support the post-pandemic recovery of undersevered BCS.

Machine learning with multimodal data for COVID-19.

In response to the unprecedented global healthcare crisis of the COVID-19 pandemic, the scientific community has joined forces to tackle the challenges and prepare for future pandemics. Multiple modalities of data have been investigated to understand the nature of COVID-19. In this paper, MIDRC investigators present an overview of the state-of-the-art development of multimodal machine learning for COVID-19 and model assessment considerations for future studies. We begin with a discussion of the lessons learned from radiogenomic studies for cancer diagnosis. We then summarize the multi-modality COVID-19 data investigated in the literature including symptoms and other clinical data, laboratory tests, imaging, pathology, physiology, and other omics data. Publicly available multimodal COVID-19 data provided by MIDRC and other sources are summarized. After an overview of machine learning developments using multimodal data for COVID-19, we present our perspectives on the future development of multimodal machine learning models for COVID-19.

The social vulnerability metric (SVM) as a new tool for public health.

OBJECTIVE: To derive and validate a new ecological measure of the social determinants of health (SDoH), calculable at the zip code or county level. DATA SOURCES AND STUDY SETTING: The most recent releases of secondary, publicly available data were collected from national U.S. health agencies as well as state and city public health departments. STUDY DESIGN: The Social Vulnerability Metric (SVM) was constructed from U.S. zip-code level measures (2018) from survey data using multidimensional Item Response Theory and validated using outcomes including all-cause mortality (2016), COVID-19 vaccination (2021), and emergency department visits for asthma (2018). The SVM was also compared with the existing Centers for Disease Control and Prevention's Social Vulnerability Index (SVI) to determine convergent validity and differential predictive validity. DATA COLLECTION/EXTRACTION METHODS: The data were collected directly from published files available to the public online from national U.S. health agencies as well as state and city public health departments. PRINCIPAL FINDINGS: The correlation between SVM scores and national age-adjusted county all-cause mortality was r = 0.68. This correlation demonstrated the SVM's robust validity and outperformed the SVI with an almost four-fold increase in explained variance (46% vs. 12%). The SVM was also highly correlated (r ≥ 0.60) to zip-code level health outcomes for the state of California and city of Chicago. CONCLUSIONS: The SVM offers a measurement tool improving upon the performance of existing SDoH composite measures and has broad applicability to public health that may help in directing future policies and interventions. The SVM provides a single measure of SDoH that better quantifies associations with health outcomes.

Invited Commentary: The Society for Epidemiologic Research Annual Meeting-Room to Improve Gender Equity.

The annual meeting of the Society for Epidemiologic Research is a prominent showcase for epidemiologists to present their research and share their expertise with peers. There are multiple paths to being on a podium at the meeting, and that role has implications for not only the speaker but also the audience. The article by Nobles et al. (Am J Epidemiol. 2021;190(9):1710-1720) represents an innovative investigation of representation among speakers at 3 recent SER annual meetings, with a primary focus on gender. Women were significantly under-represented as symposium speakers, which is an important role at the meeting. Symposium talks are invited talks and thus recognition of stature in the field. However, women were not under-represented as speakers in the concurrent contributed sessions, which are not invited talks and undergo blinded peer review. This gender contrast between the speakers at concurrent contributed sessions and the symposia is likely due to the different submission processes for the 2 types of presentations, but it could also reflect the review processes. Although the symposia are highly informative and enjoyable components of the meetings, some modifications in the submission and evaluation processes may be beneficial.

U.S. trends in elective and emergent major abdominal surgical procedures from 2002 to 2014 in older adults.

BACKGROUND: The U.S. population is aging and projected to undergo an increasing number of general surgical procedures. However, recent trends in the frequency of major abdominal procedures in older adults are currently unknown as improvements in non-operative interventions may obviate the need for major surgery. Thus, we evaluated the trends of major abdominal surgical procedures in older adults in the United States. METHODS: We performed a retrospective cohort study using the National Inpatient Sample from 2002 to 2014 with trend analysis using National Cancer Institute's Joinpoint Trend Analysis Software. We identified the average annual percent change (AAPC) in the yearly frequency of major abdominal surgical procedures in older adults (≥50 years of age). RESULTS: Our cohort included a total of 3,951,947 survey-weighted discharges that included a major abdominal surgery in adults ≥50 years of age between 2002 and 2014. Of these discharges, 2,529,507 (64.0%) were for elective abdominal surgeries, 2,062,835 (52.0%) were for female patients, and mean (SD) age was 61.4 (15.9) years. The frequency of major abdominal procedures (elective and emergent) decreased for adults aged 65-74 (AAPC: -1.43, -1.75, -1.11, p < 0.0001), 75-84 (AAPC: -2.75, -3.33, -2.16, p < 0.001), and ≥85 (AAPC: -4.07, -4.67, -3.47, p < 0.0001). The AAPC for elective procedures decreased for older adults aged 75-84 (AAPC = -1.65; -2.44, -0.85: p = 0.0001) and >85 (AAPC = -3.53; -4.57, -2.48: p < 0.0001). All age groups showed decreases in emergent procedures in 50-64 (AAPC = -1.76, -2.00, -1.52, p < 0.0001), 65-74 (AAPC = -3.59, -4.03, -3.14, p < 0.0001), 75-84 (AAPC = -3.90, -4.34, -3.46, p < 0.0001), ≥85 (AAPC = -4.58, -4.98, -4.17, p < 0.0001) age groups. CONCLUSIONS AND RELEVANCE: In this cohort of older adults, the frequency of emergent and elective major abdominal procedures in adults ≥65 years of age decreased with significant variation among individual procedure types. Future studies are needed to identify the generalizability of our findings to other surgical procedures.

Associations of loneliness and social isolation with actigraph and self-reported sleep quality in a national sample of older adults.

STUDY OBJECTIVES: To examine associations of social isolation and loneliness with sleep in older adults and whether associations differ for survey and actigraph sleep measures. METHODS: This study used data from the National Social Life, Health, and Aging Project (NSHAP), a nationally representative study of community-dwelling older adults born 1920-1947. A random one-third of participants in 2010-2011 were invited to participate in a sleep study (N = 759) that included survey questions, 72 hours of wrist actigraphy, and a sleep log. Perceived loneliness was measured using three questions from the UCLA Loneliness Scale. An index of social isolation was constructed from nine items that queried social network characteristics and social interactions. We used ordinary least squares and ordinal logistic regression to examine whether sleep measures were associated with loneliness and social isolation adjusted for potential sociodemographic confounders. RESULTS: Social isolation and loneliness had a low correlation (Spearman's correlation = 0.20). Both loneliness and social isolation were associated with actigraphy measures of more disrupted sleep: wake after sleep onset and percent sleep. Neither was associated with actigraph total sleep time. Increased loneliness was strongly associated with more insomnia symptoms and with shorter sleep duration assessed by a single question, but social isolation was not. More isolated individuals spent a longer time in bed. CONCLUSIONS: We found that both loneliness and social isolation were associated with worse actigraph sleep quality, but their associations with self-reported sleep differed. Only loneliness was associated with worse and shorter self-reported sleep.

Tobacco and marijuana use and their association with serum prostate-specific antigen levels among African American men in Chicago.

African American (AA) men experience more than twice the prostate cancer mortality as White men yet are under-represented in academic research involving prostate-specific antigen (PSA), a biomarker of prostate cancer aggressiveness. We examined the impact of self-reported tobacco (cigarette pack-years and current tobacco use including e-cigarettes) and current regular marijuana use on serum PSA level based on clinical laboratory testing among 928 AA men interviewed 2013-2018 in Chicago. We defined outcome of elevated PSA ≥ 4.0 ng/mL for logistic regression models and continuous PSA increases for general linear models. All models were adjusted for age, sociodemographic characteristics, healthcare utilization, body mass index, and self-reported health. Among 431 AA men age ≥ 55 years, we observed ∼ 5 times the odds of elevated PSA among those with > 1 pack-years of cigarette smoking vs. never-smokers (odds ratio [OR] = 5.09; 95% confidence interval [CI] = 1.57-16.6) and a quarter the odds of elevated PSA among current marijuana users vs. non-users (OR = 0.27; 95% CI = 0.08-0.96). PSA increased on average 1.20 ng/mL among other current tobacco users vs. non-users. Among older AA men, cigarette smoking history and current tobacco use were positively associated with an increase in PSA levels and current marijuana use were inversely associated with PSA levels. Future work with studies of diverse patient populations with cancer outcomes are needed to assess whether these behavioral characteristics contribute to racial/ ethnic disparities in prostate cancer outcomes. Our study provides novel evidence regarding potential differences in PSA levels among older AA men according to behavioral characteristics.

Sleep in hospitalized patients with chronic obstructive pulmonary disease: an observational study.

STUDY OBJECTIVES: The aim of this study was to compare the risk of undiagnosed sleep disorders among medical patients with chronic obstructive pulmonary disease (COPD) compared with those without COPD. METHODS: In a prospective cohort study, hospitalized medical ward patients without a known sleep disorder were screened, using validated questionnaires, for sleep disorders, such as obstructive sleep apnea and insomnia. Daily sleep duration and efficiency in the hospital were measured via wrist actigraphy. Participants were classified into two groups: those with a primary or secondary diagnosis of COPD and those without a history of COPD diagnosis. Sleep outcomes were compared by COPD diagnosis. RESULTS: From March 2010 to July 2015, 572 patients completed questionnaires and underwent wrist actigraphy. On admission, patients with COPD had a greater adjusted risk of obstructive sleep apnea (adjusted odds ratio 1.82, 95% confidence interval 1.12-2.96, P = .015) and clinically significant insomnia (adjusted odds ratio 2.07, 95% confidence interval 1.12-3.83, P = .021); no differences were observed for sleep quality or excess sleepiness on admission. After adjustment, compared with patients without COPD, patients with COPD averaged 34 fewer minutes of nightly sleep (95% confidence interval 4.2-64.0 minutes, P = .026), as well as 22.5% lower odds of normal sleep efficiency while in the hospital (95% confidence interval 3.3%-37.9%, P = .024). No statistically significant differences were observed for in-hospital sleep quality, soundness, or ease of falling asleep. CONCLUSIONS: Among hospitalized patients in medical wards, those with COPD have higher risk of OSA and insomnia and worse in-hospital sleep quality and quantity compared with those without COPD.

Associations of Sleep Characteristics With Cognitive Function and Decline Among Older Adults.

Sleep laboratory studies find that restricted sleep duration leads to worse short-term cognition, especially memory. Observational studies find associations between self-reported sleep duration or quality and cognitive function. However self-reported sleep characteristics might not be highly accurate, and misreporting could relate to cognition. In the Sleep Study of the National Social Life, Health, and Aging Project (NSHAP), a nationally representative cohort of older US adults (2010-2015), we examined whether self-reported and actigraph-measured sleep are associated with cross-sectional cognitive function and 5-year cognitive decline. Cognition was measured with the survey adaptation of the multidimensional Montreal Cognitive Assessment (MoCA-SA). At baseline (n = 759), average MoCA-SA score was 14.1 (standard deviation, 3.6) points of a possible 20. In cross-sectional models, actigraphic sleep-disruption measures (wake after sleep onset, fragmentation, percentage sleep, and wake bouts) were associated with worse cognition. Sleep disruption measures were standardized, and estimates of association were similar (range, -0.37 to -0.59 MoCA-SA point per standard deviation of disruption). Actigraphic sleep-disruption measures were also associated with odds of 5-year cognitive decline (4 or more points), with wake after sleep onset having the strongest association (odds ratio = 1.43, 95% confidence interval: 1.04, 1.98). Longitudinal associations were generally stronger for men than for women. Self-reported sleep showed little association with cognitive function.

Cognitive Function, Consent for Participation, and Compliance With Wearable Device Protocols in Older Adults.

Background: Population-based studies of older adults increasingly use wearable devices to measure activity and sleep. Whether cognitive impairment reduces consent and compliance has not been assessed. Methods: In the context of a nationally representative cohort of community-dwelling adults aged 62-90, individuals were invited to participate in a sleep and activity substudy that required wearing a wrist actigraph for 72 consecutive hours. Cognitive function in the parent study was assessed with the survey adaptation of the Montreal Cognitive Assessment, and individuals were categorized as normal, mild cognitive impairment, or dementia. Participants were asked to press an event marker on the actigraph when they started trying to fall asleep and when they awoke each day. Logistic and negative binomial regressions were used to link cognitive status to nonconsent, returning usable data, wearing the actigraph three full days, ever taking the device off-wrist during the 3-day study period, and pushing the event markers, controlling for demographics. Results: Cognitive status was not associated with nonconsent, returning usable data, off-wrist, or missing days. However, individuals classified with dementia were more likely to miss bedtime and wake-up event markers. Individuals classified as mild cognitive impairment were more likely to miss wake-up event markers. Conclusions: Impaired cognition does not seem to be a barrier to compliance with simply wearing a device but may affect compliance with additional action such as pressing event markers.

A Longitudinal Examination of Factors Associated with Network Bridging Among YMSM: Implications for HIV Prevention.

Social-environmental factors may be associated with social network stability, which has implications for HIV acquisition. However, the link between social-environmental factors, network composition and HIV risk has not been examined previously among a city-population based sample of young Black men who have sex with Men (YBMSM). Respondent driven sampling was used to recruit a cohort of 618 YMBSM. Respondents were evaluated at baseline, 9 and 18 months beginning June 2013. A logistic regression model was used to assess the relationship between bridging (i.e. having non-redundant contacts in one's network, indicating network instability) and social-environmental factors and HIV risk factors between respondents, and a conditional logit model was used to assess these relationships within respondents over time. Bridging was associated with adverse social-environmental factors and higher HIV risk, indicating that bridging may be on the explanatory pathway. Future studies should assess the extent to which network stability factors mitigate HIV risk.

The Role of Gender in Publication in The Journal of Pediatrics 2015-2016: Equal Reviews, Unequal Opportunities.

OBJECTIVES: To examine whether the gender of corresponding authors, reviewers, and editors led to differential publication recommendations and outcomes for original research articles and invited editorials submitted to The Journal of Pediatrics in 2015 and 2016. STUDY DESIGN: Names of corresponding authors, reviewers, editors, and editorial writers in The Journal of Pediatrics databases for 2015-2016 were analyzed to determine gender using computer algorithms and Internet searches. Reviewer recommendations and final editor dispositions were stratified by their gender and the gender of the corresponding authors. RESULTS: Of 3729 original manuscripts, 54.3% had female corresponding authors. Women were the associate editor (40.2% of submissions), guest editor (34.8%), or primary reviewer (37.4%), with no gender difference in editor or reviewer assignments for submissions by female vs male corresponding authors. There were no outcome differences by author gender for manuscripts overseen by female (P = .71) or male (P = .62) editors nor recommendation differences by female (P = .18) or male (P = .71) reviewers. Female editors had a lower acceptance rate overall than male editors (20.1% vs 25.6%; P < .001). Women were statistically less likely to accept and complete the invitation to peer review original articles (34.0%; 2295 of 6743) compared with men (40.0%; 3930 of 9823; P < .001). Women wrote 33 of 107 editorials (30.8%). CONCLUSIONS: There were no differences in reviewer recommendations or editor decisions for original research articles based on corresponding author gender. However, women had fewer opportunities to serve as peer reviewers and editorial writers than would be expected given their representation as academic pediatric faculty.

Work Disability Among Native-born and Foreign-born Americans: On Origins, Health, and Social Safety Nets.

Public debates about both immigration policy and social safety net programs are increasingly contentious. However, little research has explored differences in health within America's diverse population of foreign-born workers, and the effect of these workers on public benefit programs is not well understood. We investigate differences in work disability by nativity and origins and describe the mix of health problems associated with receiving Social Security Disability Insurance benefits. Our analysis draws on two large national data sources-the American Community Survey and comprehensive administrative records from the Social Security Administration-to determine the prevalence and incidence of work disability between 2001 and 2010. In sharp contrast to prior research, we find that foreign-born adults are substantially less likely than native-born Americans to report work disability, to be insured for work disability benefits, and to apply for those benefits. Overall and across origins, the foreign-born also have a lower incidence of disability benefit award. Persons from Africa, Northern Europe, Canada, and parts of Asia have the lowest work disability benefit prevalence rates among the foreign-born; persons from Southern Europe, Western Europe, the former Soviet Union, and the Caribbean have the highest rates.

Sleep and Olfaction among Older Adults.

BACKGROUND: Sleep and olfaction are both critical physiological processes that tend to worsen with age. Decline in olfaction can be an early indicator of neurodegenerative diseases, whereas poor sleep quality is associated with reduced physical and mental health. Given associations with aging-related health declines, we explored whether variations in sleep were associated with olfactory function among older adults. METHODS: We assessed the relationship between sleep characteristics and olfaction among 354 community-dwelling older adults. Olfaction was measured using a validated field and survey research tool. Sleep characteristics were measured using wrist actigraphy and with self-report of sleep problems. We fit structural equation models of latent constructs of olfaction based on olfactory task items and let this be a function of each sleep characteristic. RESULTS: Actigraph sleep quality measures were associated with odor identification, but not with odor sensitivity. Longer duration sleepers had worse odor sensitivity compared to medium (58 h) sleepers, but sleep duration was not associated with odor identification. Reported sleep problems and reported usual duration were not associated with olfaction. CONCLUSIONS: Diminished sleep quality was associated with reduced capacity to identify odors. Determining whether this is a causal association will require further study and longitudinal data.

Sleep-apnea risk and subclinical atherosclerosis in early-middle-aged retired National Football League players.

PURPOSE: Limited data from former National Football League (NFL) players suggest that obstructive sleep apnea (OSA) may be highly prevalent after retirement. It remains unclear whether the high prevalence of OSA in retired players is comparable to nonathletes. This retrospective analysis compared sleep apnea (SA) risk in retired NFL players to a community cohort (CARDIA Sleep study), and examined associations between SA risk and cardiovascular risk factors, including subclinical atherosclerosis. MATERIALS AND METHODS: Retired NFL players (n=122) were matched to CARDIA Sleep participants by age ±2 years (range 37-55 years), body mass index ±2 kg/m2, race, and male sex. Participants underwent electron-beam computed tomography to measure coronary artery calcium (CAC) and completed the Berlin Questionnaire to determine SA risk. The presence of CAC was defined as an Agatston score >0. RESULTS: Retired NFL players had a greater prevalence of high SA risk than the matched CARDIA Sleep participants (27% vs 11.5%, P=0.002). Compared to the CARDIA Sleep participants, retired players were less likely to smoke, and had higher blood pressure, lower fasting glucose levels, and higher cholesterol levels. However, there was no difference in the prevalence of detectable CAC (30% vs 30%, P=1). In both players and the community cohort, SA risk was not significantly associated with CAC after controlling for age, race, and body mass index. CONCLUSION: Retired NFL players have a greater prevalence of high SA risk but similar prevalence of CAC compared with a well-matched community cohort.

Sleep Characteristics and Daytime Cortisol Levels in Older Adults.

Objective: Older adults frequently report sleep problems and are at increased risk of cardiometabolic disruption. Experimental sleep restriction of younger adults has suggested that cortisol may be on the pathway between sleep restriction and cardiometabolic disease. We investigated whether the natural variation in sleep among older adults is associated with daytime cortisol level. Methods: Salivary cortisol samples and actigraphy sleep data were collected from a random subsample of participants in the National Social Life, Health and Aging Project, a nationally representative probability sample of adults aged 62-90 (N = 672). Salivary cortisol was measured with 3 timed samples at the beginning, middle, and end of a 2-hr in-home interview. Sleep characteristics were derived from wrist actigraphy (fragmentation, wake after sleep onset [WASO], and duration) and from survey responses about usual sleep duration and sleep problems. For each individual, a single summary daytime cortisol level was estimated by fitting a marginal longitudinal model for the 3 time-stamped cortisol samples. The resulting estimates were then regressed on each sleep measure, adjusting for sociodemographics, health behaviors, and comorbidities. Results: From actigraphy, both higher fragmentation score (ß = 0.02; 95% confidence interval [CI] = 0.00 to 0.03) and longer WASO (ß = 0.27; 95% CI = 0.04 to 0.51) were significantly associated with higher daytime cortisol; sleep duration was not. Self-reported sleep duration and sleep problems were also not associated with cortisol. Conclusion: Actigraph measures of sleep disturbance are associated with higher daytime cortisol among older adults. However, cross-sectional data cannot distinguish causal direction or whether cortisol and sleep disruption have a common cause.

Correction: Measuring Physical Activity with Hip Accelerometry among U.S. Older Adults: How Many Days Are Enough?

[This corrects the article DOI: 10.1371/journal.pone.0170082.].