Disagreement between subjective and actigraphic measures of sleep duration in a population-based study of elderly persons

Sleep duration is an important concept in epidemiological studies. It characterizes a night's sleep or a person's sleep pattern, and is associated with numerous health outcomes. In most large studies, sleep duration is assessed with questionnaires or sleep diaries. As an alternative, actigraphy may be used, as it objectively measures sleep parameters and is feasible in large studies. However, actigraphy and sleep diaries may not measure exactly the same phenomenon. Our study aims to determine disagreement between actigraphic and diary estimates of sleep duration, and to investigate possible determinants of this disagreement. This investigation was embedded in the population-based Rotterdam Study. The study population consisted of 969 community-dwelling participants aged 57-97 years. Participants wore an actigraph and kept a sleep diary for, on average, six consecutive nights. Both measures were used to determine total sleep time (TST). In 34% of the participants, the estimated TST in the sleep diaries deviated more than 1 h from actigraphically measured TST. The level of disagreement between diary and actigraphic measures decreased with subjective and actigraphic measures of sleep quality, and increased with male gender, poor cognitive function and functional disability. Actigraphically measured poor sleep was often accompanied by longer subjective estimates of TST, whereas subjectively poor sleepers tended to report shorter TST in their diaries than was measured with actigraphy. We recommend, whenever possible, to use multiple measures of sleep duration, to perform analyses with both, and to examine the consistency of the results over assessment methods.     

Racial differences in pregnancy duration and its implications for perinatal care

The average length of gestation is about 5 days shorter in black populations than in white populations. Although some of this difference is accounted for by higher preterm delivery rates in blacks, the most common gestational week of delivery at term is the 39th in black populations, the 40th in white. Black gestational age specific neonatal mortality is lower than that of whites until the 37th week of gestation, but higher thereafter. These observations suggest the hypothesis that complications of postmaturity occur sooner in black fetuses. If this hypothesis is confirmed, antepartum surveillance for signs of fetal compromise should be initiated earlier in gestation in black parturients, perhaps by setting the estimated date of confinement at 275 days after the LMP, rather than the conventional 280 days.     

Racial differences in sleep architecture: the role of ethnic discrimination

African Americans have been consistently shown to have less deep (slow wave sleep; SWS) and more light (Stages 1 and 2) sleep than Caucasian Americans. This paper explored whether discrimination, a stressor that uniquely impacts certain ethnic groups, contributes to differences in sleep architecture. The sleep of 164 African and Caucasian Americans was examined with laboratory based polysomnography (PSG). Experiences of perceived discrimination (The Scale of Ethnic Experience) and sociodemographic factors were also assessed. After adjusting for age, body mass index (BMI), socioeconomic status (SES) and smoking status, African Americans slept approximately 4.5% more total sleep time (TST) in Stage 2 sleep and 4.7% less TST in SWS than Caucasian Americans (ps < .05). Perceived discrimination was a partial mediator of ethnic differences in sleep architecture. Individuals who reported experiencing more discrimination slept more time in Stage 2 and less time in SWS (ps < .05). Results suggest that the impact of stress related to ethnic group membership plays a part in explaining differences in sleep architecture.     

Sex differences in the association between sleep duration, diet and body mass index: a birth cohort study

Sex differences in the effects of sleep duration on dietary intake and eating behaviours were examined prospectively in relation to overweight/obesity at ages 6 and 7. Using data from a representative sample (QLSCD 1998-2010) of children born in the province of Québec (Canada), 1106 children were followed to age 6 and 1015 to 7years. Average nocturnal sleep duration was surveyed annually from 2.5-6years, food-frequency and eating behaviour questionnaires were administered at age 6, and body weight and height were measured at 6 and 7years. Associations were examined longitudinally and mediation examined with adjustments for potential confounders. In boys and girls, shorter sleep duration patterns were associated significantly with less favourable dietary intakes at 6years: boys consumed vegetables and fruits less frequently and meats/alternatives more frequently than boys with longer sleep patterns; and girls consumed vegetables, fruits and milk products less frequently and soft-drinks more frequently than girls with longer sleep patterns. However, boys with shorter sleep patterns were also more likely to eat at irregular hours or to eat too much/fast at 6years. These behaviours, and not dietary intake, mediated an inverse association between sleep duration and overweight/obesity in boys. Sleep duration did not associate with any problem eating behaviours or overweight/obesity in girls. Shorter sleep in early childhood appears to associate with problematic eating behaviours in boys and diet quality in both sexes, regardless of an association with overweight/obesity. This is important for public health and should be considered in relation to other diet-related diseases.     

Towards an understanding of self-reports of sleep

Sleep research has made extensive use of self-report measures relying on a response format that requires respondents to provide single, specific numerical estimates. The cognitive processes involved in storing and retrieving sleep-related information allow only approximate numeric estimates of sleep behavior. Based on a fuzzy set model of survey responses, a response format is proposed to better capture the inherent vagueness of quantitative estimates of sleep behavior. Ninety-three adults (mean age 29.3 years) participated in two interviews, 1 month apart, consisting of questions about health-related behaviors. Questions were asked in both traditional point estimate and fuzzy response formats. A subset of questions was repeated at the end of each interview to examine test-retest reliability. Subjects filled out daily diaries each morning during the month between interviews. Quantitative estimates of usual sleep behavior were found to be highly reliable. Point estimates differed significantly from fuzzy boundary estimates. Differences between lower and upper boundary estimates indicated substantial ranges in estimates of usual sleep: total sleep time (6-8.2 h), sleep latency (26-44 min), bed time (11:25 PM-12:56 AM) and waking time (7:24-8:39 AM). Mean diary-recorded bed and waking times fell between the lower and upper boundary estimates in more than 53% of cases, and between the lower and upper extreme estimates in more than 92% of cases. Fuzzy response formats provide an opportunity to report more completely what can be recalled about sleep behavior. They also provide a useful framework for better understand the meaning of traditional point estimate formats.     

Sleep duration and overweight among elementary schoolchildren: a population-based study in Japan

Although a number of studies have investigated the relationship of sleep duration to overweight and obesity, studies conducted among population-based elementary schoolchildren have been limited in Japan. The aim of the present study was to investigate the relationship between sleep duration and overweight among elementary schoolchildren in Japan. The study subjects were all fourth-grade schoolchildren (9 or 10 years of age) in Ina-town, Saitama Prefecture, Japan from 1999 to 2008. Information concerning each subject's sex, age, and lifestyle was obtained using a self-administered questionnaire, while measurements of his or her height and weight were carried out. Childhood overweight was determined according to the definition established by the International Obesity Task Force. Data from 3,433 children were analyzed. In logistic regression analysis, a statistically significant dose-response relationship was observed between sleep duration and overweight among boys (p for trend = 0.014) but not among girls (p for trend = 0.149). Short sleep duration was associated with childhood overweight, and the sex difference in the association was observed. These findings suggested that it is important to consider sleep duration as part of any program to prevent overweight among elementary schoolchildren, especially among boys.     

Duration of sleep and breast cancer risk in a large population-based case-control study

One important function of sleep may be its contribution to the maintenance of the immune system and regulation of the circadian rhythms by melatonin. Researchers have speculated that disruption of immune functions involving cortisol levels and natural killer cell activity may increase breast cancer risk whereas increased melatonin exposure may protect against breast cancer. We conducted a multistate population-based case-control study of 4,033 women with invasive breast cancer and 5,314 community women without breast cancer in which we inquired about women's sleep habits in the recent past and during adult lifetime. Relative to women who slept 7.0-7.9 h/night, the multivariate odds ratio for developing breast cancer among women who slept an average of 9 h or more per night approximately 2 years prior to interview was 1.13 (95% CI 0.93-1.37). The multivariate-adjusted odds ratio for the continuous term was 1.06 (95% CI 1.01-1.11), suggesting a 6% increase in risk for every additional hour of sleep. Similar patterns were observed for average lifetime adult sleep duration. We found little evidence that sleeping few hours per night was associated with breast cancer risk. The results of this study suggest that increasing sleep duration is modestly associated with an increased breast cancer risk. In contrast, short duration of sleep (<7 h/night) is not substantially associated with increased risk. Further research in this area is warranted.     

Pre-pregnancy sleep duration and postpartum depression: a multicenter study in Japan

Postpartum depression (PPD) is as a major public health issue and clinical priority worldwide. This study aimed to investigate the association between pre-pregnancy sleep duration and PPD. A multicenter retrospective study was conducted using clinical data of women who delivered at term between 2014 and 2018 at 12 maternity care hospitals in Japan. A total of 15,314 women were stratified into five groups according to their pre-pregnancy sleep duration: < 6, 6–7, 7–8, 8–9, and ≥ 9 h. Univariate and multivariate regression analyses were conducted to determine whether pre-pregnancy sleep duration affects the Edinburgh Postnatal Depression Scale (EPDS) scores at 1 month postpartum. We also evaluated whether the risk for PPD differs between primipara and multipara women classified according to pre-pregnancy sleep duration. The adjusted odds ratio for high EPDS scores (≥ 9) among women who slept for < 6 h and 6–7 h was 2.08 (95% confidence interval [CI]: 1.60–2.70) and 1.41 (95% CI: 1.18–1.68), respectively, relative to that in women with 7–8 h of sleep as the reference group. A 1-h increase in sleep duration was associated with an approximately 14% reduction in the risk for high EPDS scores. The association between short sleep duration and high EPDS scores was more remarkable in multipara women than in primipara women. Short pre-pregnancy sleep duration is associated with high EPDS scores, and this association is more significant in multipara women than in primipara women. Our findings emphasize the importance of collecting information on pre-pregnancy sleep duration to identify women at a high risk for PPD.

     

Gender differences in actual and preferred nocturnal sleep duration among Finnish employed population

ObjectiveSufficient sleep is essential for health and working capacity. Shorter sleep duration on workdays is often compensated by sleeping longer during leisure days. Gender dissimilarities in sleep quality are acknowledged. Our aim was to study the less known gender differences in sleep duration.MethodsA population based study with a total of 1049 middle-aged regularly working women (n = 524) and men (n = 525). A questionnaire of sleep durations on workdays and leisure days, preferred sleep duration, with health-related quality of life and health behavior.ResultsWomen slept 14 min longer on workdays (p < 0.002) and 27 min longer on leisure days (p < 0.002) and had 32 min longer preferred sleep duration (p < 0.001) than men. Compared to workdays, women slept 1 h 57 minutes longer and men 1 h 42 min longer on leisure days (gender p < 0.001). On workdays, both women and men slept less than their preferred sleep duration and again, with more extensive difference in women (gender-interaction p < 0.001). On leisure days the excessive sleep time did not differ between genders (p = 0.346). None of the explanatory variables explained the gender differences in sleep durations.ConclusionsSleep loss on workdays is presumably more pronounced in women, since despite their longer sleep on workdays, the gender differences persist in both sleep duration on leisure days and in preferred sleep duration.     

Racial differences in health concern

An understanding of racial differences in risk-related affect may help explain racial differences in health behaviors and outcomes and provide additional opportunities for intervention. In phone interviews with a random community sample of 197 whites, 155 blacks and 163 Latinos, we assessed concern that respondents' health would be hurt by their diet, an inability to exercise, an inability to follow a doctor's recommendations and disease. A multivariate analysis of variance with follow-up profile analysis revealed that whites were less concerned than blacks and Latinos about an inability to follow their doctors' recommendations (ps < 0.01). There were no racial differences in the other health concern variables. Interventions to inform blacks and Latinos about their health risks must strike a balance between creating enough health concern to encourage health behavior but not so much that it interferes with health-promoting behaviors.     

Racial differences in atopic dermatitis

ObjectiveTo summarize studies investigating ethnical and racial differences in atopic dermatitis (AD) epidemiology, clinical features, and skin and blood phenotypes.Data SourcesPubMed literature review (years 2000-2018).Study SelectionsArticles discussing primarily human disease.ResultsHigher overall rates of AD were found in Africa and Oceania as opposed to India and Northern and Eastern Europe. In the United States, AD prevalence was found to be higher in African American (19.3%) compared with European American (16.1%) children. Although several studies have consistently found FLG loss-of-function mutations in up to 50% of European and 27% of Asian patients with AD, FLG mutations were 6 times less common in African American than in European American patients, even in patients with severe AD. Thus, FLG mutations seem to play less a pathogenic role in patients of African origin than in individuals of European or Asian ancestry. The immune phenotype of all ethnic groups was characterized by strong T_H2 activation, but important differences in immune polarization exist among the different ethnicities. Asian patients with AD had stronger T_H17/T_H22 activation than African American and European American patients with AD, whereas African American patients had the highest serum IgE levels among all groups, while largely lacking T_H1 and T_H17 activation.ConclusionAD is a heterogeneous disease that has differences among various ethnic and racial groups, which might be important for the development of future, targeted treatments and for personalized medicine approaches.     

Racial/ethnic disparities in sleep duration and sleep disturbances among pregnant and non‐pregnant women in the United States

Sleep disturbances among pregnant women are increasingly linked to suboptimal maternal/birth outcomes. Few studies in the USA investigating sleep by pregnancy status have included racially/ethnically diverse populations, despite worsening disparities in adverse birth outcomes. Using a nationally representative sample of 71,644 (2,349 pregnant) women from the National Health Interview Survey (2004–2017), we investigated relationships between self‐reported pregnancy and six sleep characteristics stratified by race/ethnicity. We also examined associations between race/ethnicity and sleep stratified by pregnancy status. We used average marginal predictions from fitted logistic regression models to estimate prevalence ratios (PRs) and 95% confidence intervals (CIs) for each sleep dimension, adjusting for sociodemographic and health characteristics. Pregnant women were less likely than non‐pregnant women to report short sleep (PR_Overall = 0.75; 95% CI, 0.68–0.82) and more likely to report long sleep (PR_Overall = 2.06; 95% CI, 1.74–2.43) and trouble staying asleep (PR_Overall = 1.34; 95% CI, 1.25–1.44). The association between pregnancy and sleep duration was less pronounced among women aged 35–49 years compared to those <35 years. Among white women, sleep medication use was less prevalent among pregnant compared to non‐pregnant women (PR_White = 0.45; 95% CI, 0.31–0.64), but this association was not observed among black women (PR_Black = 0.98; 95% CI, 0.46–2.09) and was less pronounced among Hispanic/Latina women (PR_{Hispanic/Latina} = 0.82; 95% CI, 0.38–1.77). Compared to pregnant white women, pregnant black women had a higher short sleep prevalence (PR_Black = 1.35; 95% CI, 1.08–1.67). Given disparities in maternal/birth outcomes and sleep, expectant mothers (particularly racial/ethnic minorities) may need screening followed by treatment for sleep disturbances. Our findings should be interpreted in the historical and sociocultural context of the USA.     

A prospective study of sleep duration and mortality risk in women

STUDY OBJECTIVES: It is commonly believed that 8 hours of sleep per night is optimal for good health. However, recent studies suggest the risk of death is lower in those sleeping 7 hours. We prospectively examined the association between sleep duration and mortality in women to better understand the effect of sleep duration on health. DESIGN: Prospective observational study. SETTING: Community-based. PARTICIPANTS: Women in the Nurses Health Study who answered a mailed questionnaire asking about sleep duration in 1986. INTERVENTIONS: None. MEASUREMENTS AND RESULTS: Vital status was ascertained through questionnaires, contact with next of kin, and the National Death Index. During the 14 years of this study (1986-2000), 5409 deaths occurred in the 82,969 women who responded to the initial questionnaire. Mortality risk was lowest among nurses reporting 7 hours of sleep per night. After adjusting for age, smoking, alcohol, exercise, depression, snoring, obesity, and history of cancer and cardiovascular disease, sleeping less than 6 hours or more than 7 hours remained associated with an increased risk of death. The relative mortality risk for sleeping 5 hours or less was 1.15 (95% confidence interval [CI], 1.02-1.29) for 6 hours, 1.01 (95% CI, 0.94-1.08), for 7 hours, 1.00 (reference group), for 8 hours, 1.12 (95% CI, 1.05-1.20), and for 9 or more hours 1.42 (95% CI, 1.27-1.58). CONCLUSIONS: These results confirm previous findings that mortality risk in women is lowest among those sleeping 6 to 7 hours. Further research is needed to understand the mechanisms by which short and long sleep times can affect health.     

Racial differences in ovarian cancer risk

We examined whether the previously observed lower risk of ovarian cancer among African-American women might be the result of differences in known risk factors. In a population-based, case-control study, sociodemographic, reproductive, and physical risk factors among white (669) and African-American (84) women aged 20 through 69 years with a recent diagnosis of epithelial ovarian cancer (study subjects) were compared with white (1110) and African-American (204) community control subjects. African-American women were more likely to have five or more pregnancies and to have a hysterectomy, whereas white women were more likely to have a family history of ovarian cancer. Yet, the risk and protective factors for ovarian cancer were similar among white and African-American women. As compared with white women, the odds of ovarian cancer among African-American women was significantly lower (odds ratio 0.7, 95% confidence interval [CI] 0.5 to 0.9) and remained somewhat lower after adjusting for known, important risk factors (odds ratio 0.8, 95% CI 0.6 to 1.0). Differences in the obstetric and gynecologic experiences of African-American and white women may explain some of the observed racial variability in ovarian cancer risk, but ovarian cancer risk remained lower among African-American women even after adjustment for these factors.