Midday Napping Research Articles

Sleep and risk of hip fracture and falls among middle-aged and older Chinese.

The study aimed to assess the prospective associations between sleep duration, sleep restfulness, midday napping and hip fracture (HF) and falls in a nationally representative Chinese population. Data were from the China Health and Retirement Longitudinal Study which was conducted from 2013 to 2018. In total, 10,508 individuals without a history of HF in 2013 were included. Nighttime sleep duration, sleep restfulness and midday napping were self-reported. Logistic regression analyses were performed to examine the relationships between sleep problems and HF as well as falls, adjusting for covariates. A total of 313 (3.0%) participants reported HF, and 3899 (37.1%) experienced at least one fall event over the following 5-year period. Participants who had a short sleep duration (≤ 6) were more likely to report HF (OR = 1.27, 95% CI = 1.00-1.62) and falls (OR = 1.18, 95% CI = 1.07-1.30) than those who had a normal sleep duration (6-9h) in the fully adjusted model. Participants having unrestful sleep were also more likely to report falls (OR = 1.23, 95% CI = 1.11-1.36) than those who had restful sleep. However, there was no significant association between midday napping and HF and falls. In conclusion, short sleep duration and sleep restfulness were independently associated with an increased risk of HF and falls, which may have important clinical and public health implications. Interventions to improve sleep quality may reduce the risk of HF and fall accidents among middle-aged and older people.

Associations of nighttime sleep, midday napping, and physical activity with all-cause mortality in older adults: the Seniors-ENRICA cohorts

Associations of nighttime sleep, midday napping, and physical activity with all-cause mortality in older adults: the Seniors-ENRICA cohorts

Identifying the subgroups of depression trajectories among the middle-aged and older Chinese individuals with chronic diseases: an 8-year follow-up study based on CHARLS.

Prior studies have demonstrated a prevalent occurrence of depression among the middle-aged and older Chinese individuals with chronic diseases. Nevertheless, there is limited research on the specific subgroups of depression trajectories within this population and the factors influencing these subgroups. To explore the changing trajectory and influencing factors of depression in the middle-aged and older individuals with chronic disease in China, and provide the data reference for the health management of the older adult population in China. A longitudinal cohort study was conducted using the data from the China Health and Retirement Longitudinal Study (CHARLS) in 2011, 2013, 2015, 2018, and 2020. A total of 2,178 participants with complete data were included. The level of depression was evaluated using the Center for Epidemiologic Studies Depression Scale (CESD-10). The Latent Class Mixed Models (LCMM) were employed to estimate trajectories of depressive symptoms. The Kruskal-Wallis H test and the Pearson χ 2 test were used to determine the significant factors affecting trajectory grouping. Subsequently, the multinomial logistic regression model was utilized to perform a multifactorial analysis of the variables impacting the trajectory subgroup of change in depressive symptoms. The LCMM-analysis revealed three distinct subgroups of depression trajectories: the "Low stable group" comprising 36.7% of the sample, the "Medium growth group" comprising 34.4% of the sample, and the "High growth group" comprising 28.9% of the sample. Among the baseline characteristics of different depression trajectory subgroups, there were significant differences in gender, residence, education, marital status, social activity participation, number of chronic diseases, smoking status, BMI, midday napping (minutes) and nighttime sleep duration (hours). Through multiple logistic regression analysis, our findings demonstrate that among the middle-aged and older Chinese individuals with chronic diseases, the following individuals should be the key groups for the prevention and treatment of depressive symptoms: Those who are young, female, residing in rural areas, having primary school education and below, being single, not participating in social activities, suffering from multiple chronic diseases, and having shorter naps and sleeping at night. There is heterogeneity in the subgroups of depression trajectories among the Chinese middle-aged and older individuals with chronic diseases. The focus should be on the distinct characteristics of various trajectories of depression within the realm of health management.

Effects of post-learning nap in the recognition memory for faces in habitual nappers

This study investigated the effects of diurnal nap in the recognition memory for faces in habitual nappers. Thirty volunteers with habitual midday napping (assigned as the sleep group) and 28 non-nappers (assigned as the wake group) participated in this study. Participants were instructed to memorize faces, and subsequently to perform two recognition tasks before and after nap/wakefulness, i.e., an immediate recognition and a delayed recognition. There were three experimental conditions: same faces with the same view angle (S-S condition); same faces with a different view angle (22.5°) (S-D condition); and novel faces (NF condition). A mixed repeated-measures ANOVA revealed that the sleep group exhibited significantly longer reaction times (RT) following their nap compared to those of the wake group; no significant between-group differences were observed in accuracy or sensitivity (d’). Furthermore, both groups were more conservative in the delayed recognition task compared to the immediate recognition task, but the sleep group was more conservative after their nap (vs pre-nap), reflected by the criterion (β, Ohit/Ofalse alarm). Further stepwise regression analysis revealed a positive relationship between duration of stage N3 sleep and normalized RT difference before/after nap on the S-S condition. These findings suggest that an immediate nap following face learning is associated with memory reorganization during N3 sleep in habitual nappers, rendering the memories not readily accessible.

Changes in sleep score and leisure-time physical activity, their combination, and all-cause mortality in middle-aged and older Chinese adults: The Dongfeng-Tongji cohort study

ObjectivesTo prospectively investigate the associations of longitudinal changes in sleep score and LTPA and their combination with all-cause mortality. MethodsAmong 12,543 participants (mean age: 66.1 years) from the Dongfeng-Tongji cohort, we calculated sleep score (range, 0–4, integrating bedtime, sleep duration, sleep quality, and midday napping, higher score indicating healthier sleep) and LTPA at baseline (2008–2010) and the first follow-up (2013) surveys and their 5-year changes (defining stable sleep score as no change and stable LTPA as change within 150 min/week). We prospectively documented deaths from the first follow-up survey (2013) through December 31, 2018. ResultsDuring a mean 5.5-year follow-up, 792 deaths occurred. The 5-year changes in sleep score and LTPA were inversely associated with all-cause mortality risk, regardless of their initial values. When assessing 5-year changes in sleep score and LTPA jointly, compared with the stable sleep score-stable LTPA group, the decreased sleep score-decreased LTPA group had a 40 % (5–85 %) higher all-cause mortality risk, whereas the increased sleep score-increased LTPA group had a 34 % (9–52 %) lower risk. The direction of the joint association was mainly driven by sleep score change. Participants maintaining sleep scores ≥ 3 and LTPA ≥ 150 min/week over 5 years had a 44 % (28–56 %) lower all-cause mortality risk. ConclusionsPromoting sleep hygiene and LTPA together may benefit efforts in reducing mortality risk, with particular attention to monitoring long-term sleep health.

Changes in Sleep Patterns, Genetic Susceptibility, and Incident Cardiovascular Disease in China

The associations of changes in sleep patterns with incident cardiovascular disease (CVD) are not fully elucidated, and whether these associations are modified by genetic susceptibility remains unknown. To investigate the associations of 5-year changes in sleep patterns with incident CVD and whether genetic susceptibility modifies these associations. This prospective cohort study of the Dongfeng-Tongji cohort was conducted from 2008 to 2018 in China. Eligible participants included those with complete sleep information at baseline survey (2008-2010) and the first follow-up survey (2013); participants who had no CVD or cancer in 2013 were prospectively assessed until 2018. Statistical analysis was performed in November 2023. Five-year changes in sleep patterns (determined by bedtime, sleep duration, sleep quality, and midday napping) between 2008 and 2013, and polygenic risk scores (PRS) for coronary heart disease (CHD) and stroke. Incident CVD, CHD, and stroke were identified from 2013 to 2018. Cox proportional hazards regression models were applied to estimate hazard ratios (HRs) and 95% CIs. Among 15 306 individuals (mean [SD] age, 65.8 [7.4] years; 8858 [57.9%] female and 6448 male [42.1%]), 5474 (35.78%) had persistent unfavorable sleep patterns and 3946 (25.8%) had persistent favorable sleep patterns. A total of 3669 incident CVD cases were documented, including 2986 CHD cases and 683 stroke cases, over a mean (SD) follow-up of 4.9 (1.5) years. Compared with those with persistent unfavorable sleep patterns, individuals with persistent favorable sleep patterns over 5 years had lower risks of incident CVD (HR, 0.80; 95% CI, 0.73-0.87), CHD (HR, 0.84; 95% CI, 0.76-0.92), and stroke (HR, 0.66; 95% CI, 0.54-0.82) in the subsequent 5-year period. No significant effect modification by PRS was observed for sleep pattern change and CHD or stroke risk. However, sleep pattern changes and PRS were jointly associated with the CHD and stroke risk in a dose-dependent manner, with the lowest risk being among those with persistent favorable sleep patterns combined with low PRS (HR for CHD, 0.65; 95% CI, 0.52-0.82 and HR for stroke, 0.48; 95% CI, 0.29-0.79). In this cohort study of middle-aged and older Chinese adults, individuals with persistent favorable sleep patterns had a lower CVD risk, even among those with higher genetic risk. These findings highlight the importance of maintaining favorable sleep patterns for CVD prevention.

Association between nocturnal sleep duration and midday napping and the incidence of sarcopenia in middle-aged and older adults: a 4-year longitudinal study.

Identifying treatment targets for sarcopenia is a public health concern. This study aimed to examine the association of nocturnal sleep duration and midday napping with the presence of sarcopenia in middle-aged and older adults, utilizing data from the China Health and Retirement Longitudinal Study in 2011 and 2015. A sum of 7,926 individuals (≥40 years) took part in this study. Sarcopenia was diagnosed according to the Asian Working Group for Sarcopenia. A self-reported questionnaire was used to collect data on nocturnal sleep duration and midday napping. Nocturnal sleep duration was categorized into three groups: short sleepers (<6 h), normal sleepers (6-8 h), and long sleepers (>8 h). Midday napping was coded as a dichotomous outcome (yes/no). The incidence of sarcopenia was 5.3% during the 4-year follow-up. Short sleep duration (<6 h) was substantially linked to an increased incidence of sarcopenia (OR: 1.50, 95% CI: 1.21-1.87) as compared to nocturnal sleep length (6-8 h). Adults with midday napping had a lower risk of developing sarcopenia than non-nappers (OR: 0.78, 95% CI: 0.63-0.95). We further found that short sleepers with midday napping did not have a significantly higher risk of subsequent diagnosis of sarcopenia compared to normal sleepers without midday napping. These findings imply that short sleep duration in middle-aged and older persons is related to an increased incidence of sarcopenia. However, the adverse effect of short sleep duration on sarcopenia can be compensated by midday napping.

Interaction effect of midday napping duration and depressive symptoms on subjective memory impairment among older people in China: evidence from the China health and retirement longitudinal study database

BackgroundSubjective memory impairment (SMI) is common in older people. The aim of this study was to investigate the factors influencing SMI among older people in China, with specific focus on the interaction effect of midday napping duration and depressive symptoms on the risk of SMI.MethodsUsing a dataset representative of the Chinese population from a longitudinal study of health and retirement in China, subjects with SMI were screened using the question “how do you feel about your memory now?” and the Mini-Mental State Examination. A logistic regression model was applied to explore the factors affecting SMI. Additive and multiplicative models were used to analyze the interaction effect of midday napping duration and depressive symptoms on the risk of SMI.ResultsWe enrolled 8,254 subjects included and the incidence of SMI was 63.9%. Depressive symptoms, nap time, and physical activity were influencing factors of SMI. Midday napping duration and depressive symptoms had positive additive interaction effects on the risk of SMI. When extended-length naps and depressive symptoms coexisted, the risk of SMI was 1.06 times greater than that for either alone (RERI, relative excess risk due to interaction = 0.27, 95% CI = 0.07–0.43; AP, attributable proportion = 0.14, 95% CI = 0.01–0.23; S, synergy index = 1.06, 95% CI = 0.57–1.62). When short naps and depressive symptoms coexisted, the risk of SMI was 1.2 times higher than that for either alone (RERI = 0.12, 95% CI=-0.14–0.39; AP = 0.13, 95% CI=-0.07–0.22; S = 1.20, 95% CI = 0.79–1.82).LimitationsSince this was a cross-sectional study, the cause-and-effect relationships between the associated variables cannot be inferred.ConclusionsThe interaction effect that exists between nap time and depressive symptoms in older people is important for the identification and early intervention of people at risk for SMI.

Midday Napping, Nighttime Sleep, and Mortality: Prospective Cohort Evidence in China

ObjectiveIn developed countries, midday napping and nighttime sleep duration have been linked to long-term survival; however, little is known about such effects in less developed regions. Therefore, this study aimed to assess the associations of midday napping and nocturnal sleep with mortality in middle-aged and older Chinese adults. MethodsA nationwide cohort of 15,524 adults aged ≥ 45 years was enrolled from 28 provincial regions across mainland China and followed up from 2011 to 2018, using data from the Chinese Health and Retirement Longitudinal Study. Midday napping and nighttime sleep duration were assessed using standardized questionnaires. Cox proportional hazards models with random intercepts for the surveyed provinces were used to estimate hazard ratios (HRs) of all-cause mortality, adjusting for sociodemographic characteristics, behavioral factors, and health status. ResultsA total of 1,745 deaths occurred during a median follow-up of 7.1 years, and the mean (standard deviation) age was 59 (10.1) years at baseline. Compared with non-nappers, over 60 min nappers had a higher risk of all-cause mortality [HR: 1.35, 95% confidence interval (CI): 1.17–1.56], while no significant associations were observed among < 30 min nappers. Compared with sleep duration of 6–8 h/night, both short (< 6 h) and long (≥ 8 h) sleep duration were significantly associated with increased mortality, with corresponding HR (95% CI) estimates of 1.21 (1.05–1.38) and 1.26 (1.10–1.44), respectively. We observed significant patterns for greater risks associated with longer nap duration, with a Ptrend value < 0.001 for all-cause mortality. No significant evidence of an additive interaction was identified between midday napping and nighttime sleep. ConclusionLong midday napping and inappropriate nighttime sleep were independently associated with an increased risk of all-cause mortality in middle-aged and older Chinese populations. Biological studies are needed to validate our findings and clarify the mechanisms underlying this association.

Bedtime, sleep pattern, and incident cardiovascular disease in middle-aged and older Chinese adults: The dongfeng-tongji cohort study

ObjectivesTo investigate the associations of bedtime and a low-risk sleep pattern with incident cardiovascular disease (CVD). MethodsA total of 31,500 retirees were included from the Dongfeng-Tongji cohort in 2008–2010 and 2013. Sleep information was collected by questionnaires. CVD events were identified through the health care system until December 31, 2018. Cox proportional hazards regression models were performed to estimate hazard ratios (HRs) and 95% confidence intervals (CIs). ResultsDuring an average follow-up of 7.2 years, 8324 cases of incident CVD, including 6557 coronary heart disease (CHD) and 1767 stroke, were documented. U-shaped associations of bedtime with the risks of incident CVD and stroke were observed. Compared with bedtime between 10:01 p.m.-11:00 p.m., the HR (95% CI) for CVD was 1.10 (1.01–1.20) for ≤9:00 p.m., 1.07 (1.01–1.13) for 9:01 p.m.-10:00 p.m., and 1.32 (1.11–1.58) for >12:00 a.m., respectively, mainly driven by stroke risk (22%, 14%, and 70% higher for ≤9:00 p.m., 9:01 p.m.-10:00 p.m., and >12:00 a.m., respectively). The number of low-risk sleep factors, namely bedtime between 10:01 p.m.-12:00 a.m., sleep duration of 7-< 8 h/night, good/fair sleep quality, and midday napping ≤60 min, exhibited dose-dependent relationships with CVD, CHD, and stroke risks. Participants with 4 low-risk sleep factors had a respective 24%, 21%, and 30% lower risk of CVD, CHD, and stroke than those with 0–1 low-risk sleep factor. ConclusionsIndividuals with early or late bedtimes had a higher CVD risk, especially stroke. Having low-risk sleep habits is associated with lower CVD risks.

How the time-of-day affects the EEG signatures of vigilance fluctuation

ABSTRACT Previous research suggested the homeostatic effect on the top-down control system as a major factor for daytime vigilance decrement, yet how it alters the cognitive processes of vigilance remains unclear. Using EEG, the current study measured the vigilance of 28 participants under three states: the morning, the midafternoon after napping and no-nap. The drift-diffusion model was applied to decompose vigilant reaction time into decision and non-decision components. From morning to midafternoon, vigilance declined during sustained wakefulness, but remained stable after midday napping. Increased sleep pressure negatively affected decision time and drift rate, but did not significantly alter the non-decision process. Frontocentral N2 amplitude decreased from morning to no-nap afternoon, associated with slowing decision time. In contrast, parietal P3 had no diurnal alterations during sustained wakefulness, but enhanced after napping. Pre-stimulus parietooccipital alpha power enhanced under high sleep pressure relative to low, accompanied by more lapses in no-nap vs. post-napping conditions. The homeostasis effect is a major contributor to daily vigilance fluctuation, specifically targeting top-down control processes during the pre-stimulus and decision-making stages. Under the influence of sleep homeostasis, the speed of decision-making declines with degradation in target monitoring from morning to afternoon, leading to post-noon vigilance decrement.

Positive association between weight-adjusted-waist index and dementia in the Chinese population with hypertension: a cross-sectional study

PurposeThe links between obesity and dementia remain equivocal. Therefore, this study aimed to explore the association between weight-adjusted waist index (WWI), a new anthropometric indicator reflecting obesity, and dementia in the Chinese population with hypertension.MethodsA total of 10,289 participants with hypertension were enrolled in this cross-sectional study, a subset of the China H-type hypertension registry study. WWI was calculated as waist circumference (WC) divided by the square root of bodyweight. Mini-mental state examination (MMSE) scale was performed to evaluate the cognitive function. According to educational background, different MMSE cut-off values were applied to define dementia: < 24 for participants with ≥ 7 years of education, < 20 for those with 1–6 years of education, and < 17 for illiterate participants. Multivariable linear regression and multivariable binary logistic regression analyses were conducted to assess the associations between WWI and MMSE and dementia, respectively.ResultsOverall, the mean age was 63.7 ± 9.7 years, and 49.0% were males. Multivariate linear regression analyses showed that WWI was negatively associated with MMSE (β, -1.09; 95% confidence interval [CI]: -1.24, -0.94). Consistently, multivariable binary logistic regression analyses found a positive association between WWI and the risk of dementia (odds ratio [OR], 1.45; 95% CI: 1.35, 1.56). Compared with individuals in quartile 1 of WWI, the adjusted β and OR values of WWI for MMSE and dementia were -2.28 (95% CI: -2.62, -1.94) and 2.12 (95% CI: 1.81, 2.48), respectively. Results of smoothing curve fitting confirmed the linear association between WWI and MMSE and dementia. Subgroup analysis showed a stronger association between WWI and dementia in participants with hypertension with midday napping.ConclusionWWI was independently and positively associated with dementia among the population with hypertension, especially in those with midday napping. The data suggests that WWI may serve as a simple and effective tool for the assessment of the risk of dementia in clinical practice.

Associations of multiple sleep dimensions with overall and abdominal obesity among children and adolescents: a population-based cross-sectional study.

The relationship of insufficient sleep with the increased risk of obesity has been reported, but less is known about other sleep dimensions in the sleep-obesity associations. To assess the associations of multiple sleep dimensions with overall and abdominal obesity among Chinese students. This was a cross-sectional study involving 10,686 Han students aged 9-18 from Chinese National Survey on Students' Constitution and Health (CNSSCH). We collected sex, age, regions, parental educational levels, physical activity duration and sleep-related information by questionnaire survey, and also conducted anthropometric measurements including height, weight and waist circumference (WC). Unadjusted and adjusted binary logistic regression models were used to estimate the associations of sleep-related dimensions with obesity-related indicators. Short sleep duration was associated with higher body mass index (BMI), larger WC and higher waist-to-height ratio (WHtR) in 9-12 and 16-18 age groups, whereas prolonged sleep duration on weekday was associated with higher BMI in 13-15 age group. Non-habitual midday napping and midday napping ≤0.5 h/d (vs 0.5 to 1 h/d) increased the risk of higher BMI in 13-15 age group, and the former was also associated with larger WC in 9-12 age group. Late bedtime was associated with larger WC and higher WHtR in 9-12 age group and with higher BMI and WHtR in 13-15 age group. Students aged 9-12 with social jet lag ≥2 h were found to have greater BMI after adjustment (Odds Ratio: 1.421; 95% confidence interval: 1.066-1.894). Short or overlong sleep duration, late bedtime and great social jet lag were associated with higher prevalence of overall or abdominal obesity, while moderate midday napping can effectively decrease the risk. Those findings may assist in developing preventive strategies to combat obesity epidemic.

Association of nocturnal sleep duration and midday napping with subjective poor hearing among middle-aged and older adults in China.

Hearing loss has occurred as a critical concern for aging and health. However, it remains unknown whether nocturnal sleep and midday napping duration are associated with hearing loss in middle-aged and older adults. The study comprised 9,573 adults from China Health and Retirement Longitudinal Study, who have completed the survey for sleep characteristics and subjective functional hearing. We collected self-reported nocturnal sleep duration (<5, 5 to <6, 6 to <7, 7 to <9, ≥9 h/night) and midday napping duration (≤5, 5 to ≤30, and >30 min). The sleep information was classified into different sleep patterns. The primary outcome was self-reported hearing loss events. Multivariate Cox regression models and restricted cubic splines were used to investigate the longitudinal association of sleep characteristics with hearing loss. We applied Cox generalized additive models and bivariate exposure-response surface diagrams to visualize the effects of different sleep patterns on hearing loss. We confirmed 1,073 cases of hearing loss (55.1% female) during the follow-up. After adjusting for demographic characteristics, lifestyle factors and health condition, nocturnal sleep with < 5 h was positively associated with hearing loss [hazard ratio (HR): 1.45, 95% confidence interval [CI]: 1.20, 1.75]. Individuals with napping for 5 to ≤30 min had a 20% (HR: 0.80, 95%CI: 0.63, 1.00) lower risk of hearing loss compared with those with napping ≤ 5 min. Restrictive cubic splines showed the reverse J-shaped association between nocturnal sleep and hearing loss. Moreover, we found significant joint effects of sleeping < 7 h/night and midday napping ≤ 5 min (HR: 1.27, 95% CI: 1.06, 1.52) on hearing loss. Bivariate exposure-response surface diagrams also reflected the finding that short sleep without napping existed the highest risk of hearing loss. Compared with persistently sleeping moderately (7-9 h/night), those who persistently slept < 7 h/night or shifted from < 7 h/night to moderate or > 9 h/night had higher risks of hearing loss. Inadequate nocturnal sleep was associated with an elevated risk of poor subjective hearing in middle-aged and older adults, while moderate napping decreased the risk of hearing loss. Keeping sleep stable within recommendation duration may be a useful strategy for preventing poor hearing loss.

Association of Self-Reported Sleep Characteristics and Hip Fracture: Observational and Mendelian Randomization Studies.

Previous observational studies on the relationship between sleep characteristics and fracture have yielded contradictory results. The goal of this study was to replicate the findings in a large longitudinal cohort and then conduct a Mendelian randomization (MR) analysis to infer the causality between sleep behaviors and fracture risk. Based on data from the China Health and Retirement Longitudinal Study (CHARLS) including 17,708 participants, we found that individuals with short sleep duration (<5 h) (OR [odds ratio] = 1.62, 95% CI: 1.07-2.44) or restless sleep (OR = 1.55, 95% CI: 1.10-2.19) have a higher risk of hip fracture. A U-shaped relationship between nighttime sleep duration and hip fracture risk (p-nonlinear = 0.01) was observed using restricted cubic spline regression analysis. Through joint effect analysis, we found that participants with short sleep duration (<5 h) combined with midday napping could significantly decrease hip fracture incidence. We further inferred the causal relationship between self-reported sleep behaviors and hip fracture using the MR approach. Among four sleep phenotypic parameters (sleep duration, daytime napping, chronotype, and insomnia), we found a modest causal relationship between sleep duration and fracture (OR = 0.69, 95% CI: 0.48 to 0.99, p = 0.04). However, no causal relationship was observed for other sleep traits. In conclusion, our findings suggest that short sleep duration has a potential detrimental effect on hip fracture. Improving sleep patterns is of significance for developing hip fracture preventive strategies in the middle-aged and the elderly populations.

Sleep Duration, Midday Napping, and Serum Homocysteine Levels: A Gene-Environment Interaction Study.

The associations of sleep duration and midday napping with homocysteine (Hcy) levels, and whether these sleep behaviors modify the association between genetic predisposition and Hcy levels, has yet to be investigated. We included 19,426 participants without severe health conditions at baseline from the Dongfeng−Tongji cohort. In a subgroup of 15,126 participants with genetic data, a genetic risk score (GRS) based on 18 Hcy-related loci was constructed to test the gene−sleep interactions in Hcy. Hcy levels were higher in subjects with a long sleep duration (≥9 h) and midday napping (>90 min), as compared to those who reported a moderate sleep duration (7 to <8 h) and midday napping (1−30 min) (all p values < 0.05). A long sleep duration and midday napping showed a joint effect in increasing Hcy (p for trend < 0.001). Significant interactions regarding Hcy levels were observed for a long sleep duration with GRS and MTHFR rs1801133, and long midday napping with DPEP1 rs12921383 (all p values for interaction < 0.05). Overall findings indicated that a long sleep duration and midday napping were associated with elevated serum Hcy levels, independently and jointly, and amplified the genetic susceptibility to higher Hcy.

Association of sleep behaviors, insulin resistance surrogates, and the risk of hypertension in Chinese adults with type 2 diabetes mellitus.

Our aim was to evaluate the association between midday napping, combined sleep quality, and insulin resistance surrogates and the risk of hypertension in patients with type 2 diabetes mellitus (T2DM). Data were collected using a standardized questionnaire. Binary logistic regression was performed to estimate the odds ratio (OR) and 95% confidence interval (CI) for the risk of hypertension. Systolic and diastolic blood pressure were grouped as categorical variables and unpaired two-sided Student's t-test and Spearman correlation analysis were performed to estimate the association between different blood pressure levels and insulin resistance surrogates. The overall prevalence rate of hypertension was 50%. Age (OR = 1.056, 95% CI:1.044-1.068), poor sleep quality (OR = 1.959, 95% CI:1.393-2.755), hyperlipidemia (OR = 1.821, 95% CI:1.462-2.369), family history of hypertension (OR = 2.811, 95% CI:2.261-3.495), and obesity (OR = 5.515, 95% CI:1.384-21.971) were significantly associated with an increased risk of hypertension. Midday napping for 1-30 min was negatively correlated with the risk of hypertension (OR = 0.534, 95% CI:0.305-0.936, P <0.05). Poor sleep quality and obesity are independent risk factors for hypertension. Midday napping (1-30 min) is associated with a decreased risk of hypertension in patients with T2DM.

The Association of Midday Napping With Hypertension Among Chinese Adults Older Than 45 Years: Cross-sectional Study.

Hypertension is one of the main public health issues around worldwide, and midday napping is a popular habit. The association between the two remains to be explored. The goal of the research was to explore the association of midday napping with hypertension. This study separately selected 11,439, 12,689, and 9464 Chinese respondents aged over 45 years from the China Health and Retirement Longitudinal Study 2011, 2015, and 2018 data sets. Binary logistic regression was used to explore the association of midday napping with hypertension, and the 3-step method was used to test the mediation effect of BMI. Among all respondents, the prevalence rates of hypertension were 24.6% (2818/11439) in 2011, 21.1% (2683/12689) in 2015, and 22.1% (2092/9464) in 2018. Midday napping was positively correlated with hypertension. In 2011 and 2015, napping 60 to 90 minutes had the greatest odds ratios [OR] (OR2011 1.705, OR2015 1.494). In 2018, the biggest OR came from the group napping 30 to 60 minutes (OR 1.223), and ORs of different napping durations decreased from 2011 to 2018. In addition, BMI had a partial mediation effect in 2015 and 2018. Midday napping is a potential risk factor for hypertension with BMI acting as a mediator. To prevent hypertension, avoiding prolonged duration of midday napping and taking action to maintain a normal BMI level are recommended.

Factors Associated with Subjective Well-Being of Chinese Adolescents Aged 10-15: Based on China Family Panel Studies.

(1) Background: This study aimed to explore the factors associated with the subjective well-being (SWB) of Chinese adolescents from a more comprehensive perspective and to analyze the importance of its influencing factors. (2) Methods: Obtained from the China Family Panel Studies (CFPS) 2018, the research data involved 2316 adolescents aged 10–15. By using the Chi-square test, t-test and binary logistic regression, we investigated the associations of individual-, family- and community-level factors with SWB in Chinese adolescents. To explore the rank of the influencing factors of SWB, the random forest model was set up. (3) Results: In individual-level factors, girls, who were adolescents with higher academic performance and school satisfaction, with the habit of midday napping and reading books, and with higher self-esteem, had a higher SWB. In family-level factors, mothers living at home resulted in a higher SWB, while quarrelling with their parents led to low SWB. In community-level factors, adolescents with better social relationships, social trust and who were better at telling their troubles to others had a higher SWB. Based on the random forest model, the importance degree was ranked, and the top five were decided, including self-esteem (89.949), social relations (43.457), academic performance (31.971), school satisfaction (27.651) and quarrelling with parents (19.026). (4) Conclusions: Self-esteem, social relations, academic performance, school satisfaction and quarrelling with parents are all important variables that are related to the SWB of Chinese adolescents.

Association of Midday Napping with All-Cause Mortality in Chinese Adults: A 8-Year Nationwide Cohort Study

This study aimed to investigate the longitudinal association of estimated daytime nap duration with all-cause mortality in Chinese adults. We conceived a prospective cohort design using adult survey data of the baseline and four follow-up waves (2010–2019) from China Family Panel Studies. Cox frailty models with random intercepts for surveyed provinces were used to estimate risks of all-cause mortality associated with midday napping. Trend and subgroup analyses were also performed stratified by demographic, regional and behavioral factors. Compared with non-nappers, those who reported a long napping duration (≥60 min/day) had an increased risk of all-cause mortality, while shorter napping (<60 min) showed no association with mortality. We observed significant trends for greater risks of mortality associated with longer nap duration. Long nap-associated higher risk of all-cause mortality was seen in a group of nocturnal sleep duration ≥9 h. We identified stronger associations of long nap with mortality among adults aged over 50 years, those with lower BMI (<24 kg/m2), residents in rural regions and unregular exercisers. Long midday napping is independently associated with higher risks of all-cause mortality in Chinese adults.