Subjective irregular sleep is associated with metabolic syndrome: A cross-sectional study

Sleep Duration, Midpoint, Variability, Irregularity and Metabolic Dysfunction-Associated Steatotic Liver Disease

OBJECTIVES

The relationship between actigraphy-derived sleep parameters, day-to-day deviations in sleep parameters, and metabolic dysfunction-associated steatotic liver disease (MASLD), a new definition of nonalcoholic fatty liver disease (NAFLD), remains unclear. We aimed to explore the associations of sleep duration, midpoint, variability and irregularity with MASLD risk.

METHODS

We used data from the National Health and Nutrition Examination Survey (NHANES) 2011-2014. Sleep duration and midpoint were estimated from 4 to 7 days of 24-hour actigraphy measurements. Sleep duration and midpoint standard deviation were used as indicators of sleep variability and irregularity, respectively. MASLD was diagnosed according to the multi-society Delphi consensus. Hepatic steatosis was defined as fatty liver index ≥ 60. Multivariable weighted logistic regression models were used to explore correlations and perform subgroup analyses.

RESULTS

A total of 5,316 participants were included, of whom 2,339 had MASLD. After adjusting for socio-demographic characteristics, lifestyle factors, and depression, compared to sleep variability < 60 minutes, the odds ratio (OR) [95% confidence interval (CI)] was 1.13 (0.96-1.34) for 60-90 minutes, and 1.17 (1.00-1.38) for > 90 minutes (P for trend = .034). After further adjustment for other sleep variables, short sleep duration (<7 hours) was associated with a 24% higher risk of MASLD (OR: 1.24, 95% CI: 1.01-1.53); compared to sleep irregularity < 38 minutes, OR (95% CI) was 1.27 (1.02-1.59) for 38-61 minutes and 1.43 (1.24-1.65) for > 61 minutes (P for trend = .003).

CONCLUSION

In addition to sleep duration, sleep irregularity may need to be considered in the prevention of MASLD.

Diurnal patterns of accelerometer-measured physical activity and sleep and risk of all-cause mortality: a follow-up of the National Health and Nutrition Examination Surveys (NHANES)

BACKGROUND

Physical activity and sleep are established modifiable lifestyle factors, but the optimal time of the day of these behaviours for health is unknown. This study examined the independent and joint associations of diurnal patterns of physical activity and sleep with all-cause mortality.

METHODS

This prospective cohort study included 6,673 participants who have attended the accelerometer assessment in the 2011-2014 National Health and Nutrition Examination Surveys (NHANES). Diurnal patterns of accelerometer-measured physical activity and sleep were identified using K-means clustering analysis. All-cause mortality was ascertained from the accelerometer measurement to December 31, 2019 (median follow-up 6.8 years). Survey-weighted Cox proportional hazard models were performed to estimate the independent and joint associations of diurnal patterns of physical activity and sleep with all-cause mortality.

RESULTS

Diurnal patterns identified were: early-morning (32.4%), midday (42.5%), and late-afternoon (25.1%) for physical activity; and irregular sleep (37.4%), morning lark (33.6%), and night owl (29.0%) for sleep. After adjusting for volume of physical activity, sleep duration and other potential covariates, the early-morning physical activity pattern (hazard ratio 1.36, 95% confidence interval 1.13-1.64) and irregular sleep pattern (1.42, 1.01-1.99) were independently associated with higher risk of all-cause mortality, compared with midday physical activity and morning lark sleep patterns, respectively. In addition, participants with the combined pattern of early-morning physical activity and irregular sleep had higher risk of all-cause mortality compared to those with midday physical activity combined with a morning lark sleep pattern (1.92, 1.33-2.78). Several sociodemographic differences were observed in the strength of these associations.

CONCLUSIONS

Wearable activity-rest monitoring data showed that peak physical activity in the early morning and irregular sleep diurnal patterns are associated with increased mortality risk, and the combination of these patterns further exaggerated the risk. Public health program should acknowledge that the diurnal patterns of physical activity and sleep, in addition to their duration and frequency, may play a crucial role in lifestyle-based health promotion and management strategies.

Impact of Korean Military Service on the Prevalence of Steatotic Liver Disease: A Longitudinal Study of Pre-enlistment and In-Service Health Check-Ups

Background/Aims

Young Korean men are obligated to serve in the military for 18 to 21 months. We investigated the effects of military service on steatotic liver disease (SLD) and other metabolic parameters.

Methods

Pre-enlistment health check-up performed from 2019 to 2022 and in-service health check-up performed from 2020 to 2022 were merged as paired data. SLD was defined as a hepatic steatosis index of 36 or higher. Hypertension (HTN) and hypertriglyceridemia were also included in the analysis.

Results

A total of 503,136 paired cases were included in the analysis. Comparing pre-enlistment and in-service health check-ups, the prevalence of SLD (22.2% vs 17.6%, p<0.001), HTN (7.6% vs 4.3%, p<0.001), and hypertriglyceridemia (8.1% vs 2.9%, p<0.001) decreased during military service. In terms of body mass index, the proportion of underweight (8.2% vs 1.4%, p<0.001) and severely obese (6.1% vs 4.9%, p<0.001) individuals decreased over time. Regarding factors associated with SLD development and resolution, age was positively associated with SLD development (odds ratio, 1.146; p<0.001) and a health check-up interval of <450 days was a protective factor for SLD development (odds ratio, 0.746; p<0.001). Those serving in the marines were less likely to develop SLD, whereas those serving in the navy were more likely to develop SLD. Serving in the army or the navy was negatively associated with SLD resolution, whereas serving in the air force was positively associated with SLD resolution.

Conclusions

The prevalence of SLD, HTN, and hypertriglyceridemia decreased substantially during Korean military service.

Circadian misalignment proxies, BMI, and chronic conditions: the role for weekday to weekend sleep differences

OBJECTIVE

To evaluate whether social jet lag (SJL) and weekend catch-up sleep (CUS), proxies of circadian misalignment, were associated with BMI and chronic conditions.

METHODS

Participants (n = 2,050,18-65y) were part of a virtual cross-sectional and population-based research. We examined CUS and SJL as continuous and categorical (< 1 h,1-2 h, > 2 h). Linear regression analyses were performed to assess the differences in BMI (outcome) associated with CUS and SJL. Restricted cubic splines were performed to explore the shape of the relationship between weekday-to-weekend variability in sleep duration, midpoint, wake time, and bedtime. Logistic regression models were used to estimate ORs(95%CIs) for chronic conditions and overweight related to CUS and SJL. Analyses were adjusted for sleep duration, biological and behavior-related variables.

RESULTS

We found a positive association of SJL and CUS with BMI. The effects remained even after adjustment for weekly sleep duration and demonstrated a proportional increase with the magnitude of sleep variability. Among participants with SJL > 2 h, BMI increased by 2.29 kg/m2 (95%CI:0.84;3.74,p:0.002). They also had 129% higher odds of chronic conditions (95%CI:1.16;4.52, p:0.01) and 119% higher odds of overweight (95%CI: 1.20;3.98,p:0.01). Individuals with CUS > 2 h presented 78% higher odds of overweight (95%CI:1.27;2.50,p:0.001) and an increase of 1.61 kg/m2 in BMI (95%CI: 0.81; 2.40,p < 0.001).

CONCLUSIONS

Our findings, which demonstrate that even a slight weekend sleep extension and variability of just 1 h is associated with higher values of BMI, suggest incorporating measures for sleep consistency and regularity into clinical protocols and public health guidelines to prevent and treat obesity and related diseases.

Investigation of the relationship between sleep-related parameters and metabolic syndrome (MetS) among youths in the Southeast of Iran

BACKGROUND AND AIM

There are few studies and inconsistent findings on the role of sleep-related parameters in the development of metabolic syndrome (MetS) among youths. In this study, we aim to investigate the relationship between sleep-related parameters and MetS among youths in a large sample size in Rafsanjan, a region in the southeast of Iran.

METHODS

The current cross-sectional study was performed on 3,006 young adults aged 15-35, who registered for Rafsanjan Youth Cohort Study (RYCS), as part of Rafsanjan Cohort Study (RCS)). In fact, RCS is a branch of the prospective epidemiological research studies in Iran (PERSIAN). In the present study, we included 2,867 youths after excluding some subjects with missing information on MetS components. MetS was diagnosed based on Adult Treatment Panel III (ATP III) criteria. Besides, data on sleep-related parameters were collected by self-report questionnaires.

RESULTS

The overall prevalence of MetS was 7.74% among the participants. In addition, bedtime, wake time, napping, night shift work, and sleep duration per night and day had no association with the higher odds of having MetS. In contrast, long sleep duration at night was associated with the lower odds of high waist circumference (WC) (OR: 0.82,95% CI :0.67-0.99).

CONCLUSION

In the present study, long sleep duration at night was associated with lower odds of central obesity. However, more longitudinal studies with the objective measurement of sleep-related parameters are needed to verify the associations reported in the current study.