Association of accelerometer-measured sleep duration and different intensities of physical activity with incident type 2 diabetes in a population-based cohort study

Purpose:The aim of the current study was to investigate the association of accelerometer-measured sleep duration and different intensities of physical activity(PA)with the risk of incident type 2 diabetes in a population-based prospective cohort study.Methods:Altogether,88,000 participants(mean age=62.2±7.9 years,mean±SD)were included from the UK Biobank.Sleep duration(short:<6 h/day;normal:6-8 h/day;long:>8 h/day)and PA of different intensities were measured using a wrist-won accelerometer over a 7-day period between 2013 and 2015.PA was classified according to the median or World Health Organization-recommendation:total volume of PA(high,low),moderate-to-vigorous PA(MVPA)(recommended,not recommended),and light-intensity PA(high,low).Incidence of type 2diabetes was ascertained using hospital records or death registries.Results:During a median follow-up of 7.0 years,1615 incident type 2 diabetes cases were documented.Compared with normal sleep duration,short(hazard ratio(HR)=1.21,95%confidence interval(95%CI):1.03-1.41)but not long sleep duration(HR=1.01,95%CI:0.89-1.15)was associated with excessive type 2 diabetes risk.This increased risk among short sleepers seems to be protected against by PA.Compared with normal sleepers with high or recommended PA,short sleepers with low volume of PA(HR=1.81,95%CI:1.46-2.25),not recommended(below the World Health Organization-recommended level of)MVPA(HR=1.92,95%CI:1.55-2.36),or low light-intensity PA(HR=1.49,95%CI:1.13-1.90)had a higher risk of type 2 diabetes,while short sleepers with a high volume of PA(HR=1.14,95%CI:0.88-1.49),recommended MVPA(HR=1.02,95%CI:0.71-1.48),or high light-intensity PA(HR=1.14,95%CI:0.92-1.41)did not.Conclusion:Accelerometer-measured short but not long sleep duration was associated with a higher risk of incident type 2 diabetes.A higher level of PA,regardless of intensity,potentially ameliorates this excessive risk.

Wild Nutrition’s Food-Grown® Magnesium Supplementation Increases Sleep Quality and Sleep Duration and Reduces Stress in a Healthy Adult Population: A Double-Blind, Randomised, Placebo-Controlled Study

Background: Magnesium, an essential mineral crucial for various bodily functions, has been shown to positively influence sleep patterns. This study aimed to evaluate the efficacy of Food-Grown® magnesium in enhancing sleep quality and duration, as well as overall well-being. Methods: Eighty participants were randomly assigned to receive either 80 mg of Food-Grown® magnesium or a placebo (microcrystalline cellulose) daily for 8 weeks. Participants completed questionnaires assessing sleep quality, daytime drowsiness, quality of life, anxiety, and stress levels. Additionally, participants maintained daily sleep diaries and wore wrist-worn actigraphy devices. The primary outcome measured was the change in sleep quality and duration. Results: Seventy-one participants fulfilled all study requirements (35 in the active group and 36 in the placebo group). Magnesium supplementation significantly improved reported sleep quality, with the active group showing a 32% increase compared to 16% in the placebo group (p = 0.034). Moreover, magnesium supplementation led to a decrease in reported stress scores at week 8 compared to the placebo group (3.7 ± 2.6 vs. 5.5 ± 3.1, respectively). Both the magnesium and placebo groups exhibited significant increases in reported sleep duration and reductions in time to fall asleep, sleep disturbance, sleep latency, sleep medication usage, and total Pittsburgh Sleep Quality Index score at week 8 compared to baseline. Conclusion: Magnesium supplementation notably enhanced sleep quality and reduced stress levels compared to the placebo group. These findings highlight the potential of magnesium as a beneficial supplement for improving sleep quality and overall well-being.

A Proposal on the Novel Method to Estimate Optimal Sleep Duration Based on Self-Reported Survey Data

Background: Many adolescents have a sleep debt. Individuals sleeping for their optimal sleep duration are expected to experience no sleepiness. Then, it is important to recognize one’s optimal sleep duration to reduce sleep debt. However, there is no simple method to determine this value. Since body mass index and sleep duration exhibit a U-shaped association, it is expected that a person taking optimal sleep duration would show no marked deviation from the mean body mass index value for the population evaluated. By using self-reported sleepiness and standardized body mass index, this study aimed to estimate individual optimal sleep duration. Methods: Data from 2540 grade 5 - 11 students were used. Students who declared no sleepiness during class and also had a gender- and grade-standardized body mass index of ±1.5 were termed ideal students. The average sleep durations of ideal students were compared with those of non-ideal students. The differences of sleep duration between ideal and no-ideal students were added to habitual sleep duration of each non-ideal student to obtain assumed optimal sleep duration. A multiple regression line to predict assumed optimal sleep duration was calculated using the least squares method. Results: The mean sleep duration of 666 ideal students exceeded the lower limit of daily sleep duration proposed as “may be appropriate” for children aged 6 - 17 years by National Sleep Foundation of the USA, being longer than those of non-ideal students. Significant regression formula for assumed optimal sleep duration was obtained (adjusted R2 = 0.996, p Conclusions: No contradiction was identified in the sleep duration obtained from ideal students as with optimal sleep duration. Although further studies to confirm the current estimation are needed, a simple formula to estimate individual optimal sleep duration through easily obtainable parameters was proposed.

Report on Childhood Obesity in China (10): Association of Sleep Duration with Obesity

Objectives To explore the association of sleep duration with obesity among children in urban areas of China.Methods A total of 6 576 children（3 293 boys and 3 283 girls） aged 7-11 years were randomly selected from 36 primary schools in 6 metropolitan cities in China.A 7-day Physical Activity Recall was used to assess the sleep duration and physical activity level.The height,weight,waist circumference（WC） and percentage of body fat（%BF,as determined by bioelectrical impedance analysis technique） were measured by following the standardized operation procedures.The information on demography,lifestyle and eating habits was collected with a self-administered questionnaire from participants and their parents.Results The average sleep duration per night in the children was 9.7 h with the decreasing trends along with the increase of age（P0.05）.The sleep duration was negatively associated with body mass index（BMI） and WC in both boys and girls after adjustment for confounders（β value-0.23 and-0.82 for boys,-0.24 and-0.91 for girls,respectively,P0.01）.However,no significant association of sleep duration with %BF was found.Children who slept less than 9.0 h per night had a higher risk for overweight and obesity（OR=1.29,95% CI：1.01,1.64） and abdominal obesity（OR=1.38,95% CI：1.04,1.83） as compared with those who slept for 10.0-10.9 h.Conclusions Short sleep duration is associated with obesity.It is important to ensure adequate sleep duration of children and foster their healthy lifestyle at an early stage of life.

Gender-specific Association of Sleep Duration with Body Mass Index,Waist Circumference,and Body Fat in Chinese Adults

Objective To examine the association between habitual sleep duration and obesity among Chinese adults. Methods The association of sleep duration and obesity was investigated among 7,094 community-dwelling Chinese adults. Sleep duration was self-reported. In this study, obesity was defined as follows： body mass index （BMI） ≥ 28 kg/m^2, waist circumference （WC） ≥ 85 cm in men and ≥ 80 cm in women, and percent body fat （%BF） ≥ 25 in men and ≥ 35 in women. Logistic and quantile regressions were employed to examine relationships of interest. Results Overall, 6.42% of the participants reported short sleep durations （〈 6 h/d） while 14.71% reported long （≥ 9 h/d） sleep durations. Long sleepers （≥ 9 h/d） represented a greater frequency of women with obesity [odds ratio （OR）： 1.30; 95% confidence interval （CI）, 1.02-1.67] and high body fat （1.43, 1.04-1.96） than those who slept 7-8 h/d. An association between long sleep times and higher BMI estimations was found across the 10th-75th percentile of the BMI distribution. Among men, long sleepers （≥ 9 h/d） presented lower risks of developing abdominal obesity compared with individuals who slept 7-8 h/d （OR = 0.79, 95% CI： 0.44-0.99）. Conclusion Our study suggests that long sleep durations are associated with general obesity in Chinese women but reduced waist circumferences in men. Confirmatory studies are needed to determine the heterogeneous association of sleep time and obesity by gender.

Predicted 10-year Cardiovascular Disease Risk and Its Association with Sleep Duration among Adults in Beijing-Tianjin-Hebei Region,China

Objective The study aims to predict 10-year cardiovascular disease(CVD)risk and explore its association with sleep duration among Chinese urban adults.Methods We analyzed part of the baseline data of a cohort that recruited adults for health screening by cluster sampling.The simplified Pittsburgh Sleep Quality Index(PSQI)and Framingham 10-year risk score(FRS)were used to measure sleep duration and CVD risk.Demographic characteristics,personal history of chronic diseases,lifestyle factors were collected using a questionnaire.Height,weight,total cholesterol(TC),and high-density lipoprotein cholesterol(HDL-C)were also measured.Multiple logistic regression models were performed to explore the association of sleep duration with the predicted CVD risk.Results We included 31,135 participants(median age 44 years,53.02%males)free of CVD,cerebral stroke,and not taking lipid-lowering agents.Overall,14.05%,and 25.55%of participants were at medium and high predicted CVD risk,respectively.Short sleep was independently associated with increased odds of medium to high risk of predicted 10-year CVD among males(OR=1.10;95%CI:1.01–1.19)and increased odds of medium to high and high risk of predicted 10-year CVD among females(OR=1.23;95%CI:1.08–1.40;OR=1.27;95%CI:1.11–1.44).In contrast,long sleep had no association with cardiovascular risk.Conclusion A substantial number of adults free of CVD were at high 10-year CVD risk.Short sleep was associated with increased odds of predicted CVD risk.

Night Sleep Duration and Risk of Cognitive Impairment in a Chinese Population： A Cross-sectional Study

Objective Although sleep is one of the most important health-related behavioral factors, the association between night sleep duration and cognitive impairment has not been fully understood. A cross-sectional study was conducted with a random sample of 2,514 participants （≥ 40 years of age; 46.6% women） in China to examine the association between night sleep duration and cognitive impairment. Methods Night sleep duration was categorized as ≤ 5, 6, 7, 8, or ≥ 9 h per night. Cognitive function was measured using the Mini-Mental State Examination. A multivariate regression analysis was used to analyze the association of night sleep duration with cognitive impairment. A total of 122 participants were diagnosed with cognitive impairment. Results A U-shaped association between night sleep duration and cognitive impairment was found. The odds ratios （95% confidence intervals） of cognitive impairment （with 7 h of daily sleep being considered as the reference） for individuals reporting ≤ 5, 6, 8, and ≥ 9 h were 2.14 （1.20-3.83）, 1.13 （0.67-1.89）, 1.51 （0.82-2.79）, and 5.37 （1.62-17.80）, respectively （P ≤ 0.01）. Conclusion Short or long night sleep duration was an important sleep-related factor independently associated with cognitive impairment and may be a useful marker for increased risk of cognitive impairment.

Associations of sleep duration with childhood obesity: findings from a national cohort study in China

Objective:Examine effect of sleep duration on children’s risk of overweight and obesity;and study associations between activities in the last hour before bedtime and sleep outcomes(sleep duration,sleep quality,and sleep onset latency).Methods:Children’s data were recruited using a questionnaire survey from a nationally representative sample of children(n=10279)in China in 2013‒2016.Mixed-effects models were used to test associations among variables stratified by sex.Results:Sleep duration was positively associated with BMI in boys(β=0.04,P=0.021).Girls with short sleep durations(<8 h/d)tended to have higher BMI values than those with normal sleep durations(8‒9 h/d)(β=0.12,P=0.063).The top three activities were playing electronic devices(Factor 1),doing homework,and reading(combined as Factor 2).Factors 1 and 2 were both significantly associated with sleep duration(β=0.17,P<0.001;β=−0.26,P<0.001,respectively).Conclusion:Sleep duration seems to affect BMI in Chinese children.Using electronic devices and reading before bedtime influenced sleep duration.Good bedtime habits and sleep duration can help weight management in children.

Association between drinking behavior and sleep duration in Chinese adults: findings from the China Health and Nutrition Survey

Background:To examine the association between alcohol drinking and short sleep duration among Chinese adults.Methods:Based on inclusion and exclusion criteria,28,167 records of 15,074 adults longitudinal data were obtained from the China Health and Nutrition Survey for the period from 2004 to 2011.A multilevel logistic regression model was employed to explore the association between alcohol drinking and sleep duration.Results:Compared with nondrinking participants,a high drinking frequency was positively correlated with a short sleep duration in both the males(odds ratio(OR)=1.33,95%confidence interval(CI)=1.20–1.48,P<0.001)and females(OR=1.60,95%CI=1.18–2.18,P=0.003)before the covariates were adjusted.After adjusting for age,residence area,education level,marital status,smoking,coffee consumption,tea consumption,and activity level,this association remained significant in the males(OR=1.31,95%CI=1.17–1.46,P<0.001)but not in the females(OR=1.16,95%CI=0.85–1.59,P=0.340).Conclusion:The present results suggest that a high drinking frequency was positively correlated with a short sleep duration in male population.Comprehensive measures therefore need to be implemented to improve sleep duration,especially to increase awareness of the dangers of drinking alcohol.

Association between sleep duration and overweight/obesity among Chinese children and adolescents:a longitudinal study

Background:To determine the associations between sleep duration and overweight/obesity in Chinese children and adolescents.Methods:This longitudinal study analyzed 3,126 children and adolescents aged 7 to 18 years who had participated in the China Health and Nutrition Survey during 2004-2011.Sleep duration was classified into<9 h,9-10 h,and>10 h for children aged 7-12 years,and<8 h,8-9 h,and>9 h for adolescents aged 13-18 years.Results:After adjusting for confounder,short sleep duration was associated with overweight/obesity for girls aged 7-12 years(β=4.32,95%confidence interval=1.27 to 7.37,P=0.006)and boys aged 13-18 years(β=3.38,95%confidence interval=2.01 to 4.74,P<0.001).No statistically significant association was found among the other 2 groups.Meanwhile,long sleep duration was not statistically significant at any age.Conclusion:The association between short sleep duration and overweight/obesity to be dependent on both age and gender.

Optimal Total Sleep Duration per Day to Maintain Health-Related Quality of Life in Male Collegiate Athletes:A Cross-Sectional Study

Purpose This study investigated the optimal total sleep duration per day required by collegiate athletes to maintain the physical and mental health-related quality of life(HRQOL),compared with non-athlete students.Methods In this cross-sectional study,a questionnaire survey was conducted to assess demographic variables,lifestyle and sleep habits,and HRQOL in 392 collegiate students(non-athletes,n=174;athletes,n=218).Physical component summary(PCS)and mental component summary(MCS)were assessed using the short-form-8 health survey.Participants with both good PCS and MCS were defined as having a good HRQOL.To confirm an association between the total sleep duration per day and good HRQOL,logistic regression analyses were conducted in non-athlete students and collegiate athletes separately.Subsequently,receiver-operating curve(ROC)analyses were performed for the detection of the cut-off point of total sleep duration per day sufficient to maintain a good HRQOL.Results The average total sleep duration per day was 7 h 19 min for collegiate athletes,and 78.9%of them had a worse PCS.The cut-off point of total sleep duration per day to maintain good HRQOL for collegiate athletes was 7.92 h(area under ROC,0.64;P=0.038;sensitivity,75.4%;specificity,57.9%),which was longer than 6.79 h for non-athlete students.Conclusion Collegiate athletes required longer nocturnal sleep than non-athlete students.Nevertheless,their habitual nocturnal sleep duration was shorter compared to their optimal duration;around 70%of them faced chronic insufficient sleep.Improving sleep habits and sleep education is important in maintaining their good health-related quality of life.

Non-alcoholic fatty liver disease and sleep disorders

Studies have shown that non-alcoholic fatty liver disease(NAFLD)may be associated with sleep disorders.In order to explore the explicit relationship between the two,we systematically reviewed the effects of sleep disorders,especially obstructive sleep apnea(OSA),on the incidence of NAFLD,and analyzed the possible mechanisms after adjusting for confounding factors.NAFLD is independently associated with sleep disorders.Different sleep disorders may be the cause of the onset and aggravation of NAFLD.An excessive or insufficient sleep duration,poor sleep quality,insomnia,sleep-wake disorders,and OSA may increase the incidence of NAFLD.Despite that some research suggests a unidirectional causal link between the two,specifically,the onset of NAFLD is identified as a result of changes in sleep characteristics,and the reverse relationship does not hold true.Nevertheless,there is still a lack of specific research elucidating the reasons behind the higher risk of developing sleep disorders in individuals with NAFLD.Further research is needed to establish a clear relationship between NAFLD and sleep disorders.This will lay the groundwork for earlier identification of potential patients,which is crucial for earlier monitoring,diagnosis,effective prevention,and treatment of NAFLD.

Association between sleep duration and incidence of type 2 diabetes in China: the REACTION study

Backgrounds: Inadequate sleep duration is associated with a higher risk of type 2 diabetes and the relationship is nonlinear. We aim to assess the curve relationship between night sleep duration and the incidence of type 2 diabetes in China.Methods: A cohort of 11,539 participants from the REACTION study without diabetes at baseline (2011) were followed until 2014 for the development of type 2 diabetes. The average number of hours of sleep per night was grouped. Incidence rates and odds ratios (ORs) were calculated for the development of diabetes in each sleep duration category.Results: Compared to people who sleep for 7 to 8 h/night, people with longer sleep duration (≥9 h/night) had a greater risk of type 2 diabetes (OR: 1.27;95% CI: 1.01-1.61), while shorter sleep (<6 h/night) had no significant difference in risk of type 2 diabetes. When the dataset was stratified based on selected covariates, the association between type 2 diabetes and long sleep duration became more evident among individuals <65 years of age, male, body mass index <24 kg/m2 or with hypertension or hyperlipidemia, no interaction effects were observed. Furthermore, compared to people persistently sleeping 7 to 9 h/night, those who persistently slept ≥9 h/night had a higher risk of type 2 diabetes. The optimal sleep duration was 6.3 to 7.5 h/night.Conclusions: Short or long sleep duration was associated with a higher risk of type 2 diabetes. Persistently long sleep duration increased the risk.

Sleep Duration and Factors Related to Sleep Loss in 3-14-Year-Old Children in Beijing： A Cross-Sectional Survey

Background： It is known that short sleep duration adversely affects children＇s behavior and physical development. This study aimed to investigate the status of sleep duration in 3-14-year-old children in Beijing and explore the related factors of sleep loss with them. Methods： In this study, a cross-sectional study of random stratified cluster sampling was conducted on 3-14-year-old children and adolescents in Beijing. According to the proportion of children in each district and school, the final cohort included a total of 11 kindergartens, 7 primary schools, and 8 junior high schools from 7 districts of Beijing. Children of sampled classes were included, and their parents were invited to fill a series of questionnaires including the simplified Chinese version of Pediatric Sleep Questionnaire, Sleep Questionnaire Scale, and Hong Kong-Children Sleep Questionnaire about the performance of the last 6 months. Results： Out of the total 11,420 questionnaires, 9198 questionnaires were valid and effective with the response rate of 80.54%. The age of the investigated children was 8.8 ± 3.8 years, including 4736 males and 4462 females. The daily sleep duration of children in Beijing was 9.7 ± 0.7 h. The prevalence of sleep loss （〈9 h/day） of children in Beijing was 11.8%. The daily sleep duration of children aged 〈6, 6 ≤ age 〈11, and ≥11 years was 9.7 ± 0.6 h, 9.6 ± 0.6 h, and 9.5 ± 0.8 h, respectively. The sleep duration reduced significantly in children aged ≥11 years as compared to younger children in Beijing which was mainly contributed by the variation tendency of sleep duration on weekdays. The multivariate logistic regression analysis identified factors associated with sleep loss （P 〈 0.05）： male （odds ratio [OR] = 1.32, 95% confidence interval [CI ]： 1.15-1.51 ）, age ≥11 years （OR = 2.37, 95% CI： 1.92-2.93）, overweight （OR = 1.34, 95% CI： 1.17-1.54）, family history of snoring （OR - 1.35, 95% CI： 1.13-1.61 ） and activities before bedtime with watching TV （OR = 1.24, 95% CI： 1.08 1.43）, sports （OR = 1.22, 95% C/： 1.01-1.48）, playing cellphone （OR = 1.91,95% CI： 1.31-2.73） and surfing the Internet （OR = 1.27, 95% CI： 1.06-1.52） and among them age 〉11 years and playing cellphone betbre bedtime had greater impact on children＇s short sleep duration than that of other factors. Conclusions： Sleep loss was common among 3-14-year-old children in Beijing. Sleep duration decreased with age, especially among children over 11 years old. Factors associated with sleep loss covered sociodemographic characteristics, family sleep habits and routine activities before bedtime, and among those variables, age ≥11 years and playing with cellphones before bedtime had a greater impact on sleep duration, indicating that existing sleep loss in 3-14-year-old children could be, at least partly, improved by paying more attention to children aged of l I years or entering Grade 5 and Grade 6 and to children with a family history of snoring; by reducing the use of electronic products betbre bedtime, especially cellphones; by managing weight and keeping fit; and by improving the bedtime routine.

Relationship of sleep duration and annual changes in sleep duration with the incidence of gastrointestinal cancers:a prospective cohort study

Background:Prospective analyses have yet to identify a consistent relationship between sleep duration and the incidence of gastrointestinal(GI)cancers.The effect of changes in sleep duration on GI cancer incidence has scarcely been studied.Therefore,we aimed to examine the association between baseline sleep duration and annual changes in sleep duration and GI cancer risk in a large population-based cohort study.Methods:A total of 123,495 participants with baseline information and 83,511 participants with annual changes in sleep duration information were prospectively observed from 2006 to 2015 for cancer incidence.Cox proportional-hazards models were used to calculate hazard ratios(HRs)and their confidence intervals(CIs)for GI cancers according to sleep duration and annual changes in sleep duration.Results:In baseline sleep duration analyses,short sleep duration(≤5 h)was significantly associated with a lower risk of GI cancer in females(HR:0.31,95%CI:0.10-0.90),and a linear relationship between baseline sleep duration and GI cancer was observed(P=0.010),especially in males and in the>50-year-old group.In the annual changes in sleep duration analyses,with stable category(0 to-15 min/year)as the control group,decreased sleep duration(≤-15 min/year)was significantly associated with the development of GI cancer(HR:1.29;95%CI:1.04-1.61),especially in the>50-year-old group(HR:1.32;95%CI:1.01-1.71),and increased sleep duration(>0 min/year)was significantly associated with GI cancer in females(HR:2.89;95%CI:1.14-7.30).Conclusions:Both sleep duration and annual changes in sleep duration were associated with the incidence of GI cancer.

Deconstructing athletes’sleep:A systematic review of the influence of age,sex,athletic expertise,sport type,and season on sleep characteristics

Purpose:This systematic review aimed to describe objective sleep parameters for athletes under different conditions and address potential sleep issues in this specific population.Methods:PubMed and Scopus were searched from inception to April 2019.Included studies measured sleep only via objective evaluation tools such as polysomnography or actigraphy.The modified version of the Newcastle-Ottawa Scale was used for the quality assessment of the studies.Results:Eighty-one studies were included,of which 56 were classified as medium quality,5 studies as low quality,and 20 studies as high quality.A total of 1830 athletes were monitored over 18,958 nights.Average values for sleep-related parameters were calculated for all athletes according to sex,age,athletic expertise level,training season,and type of sport.Athletes slept on average 7.2±1.1 h/night(mean±SD),with 86.3%±6.8%sleep efficiency(SE).In all datasets,the athletes’mean total sleep time was<8 h.SE was low for young athletes(80.3%±8.8%).Reduced SE was attributed to high wake after sleep onset rather than sleep onset latency.During heavy training periods,sleep duration and SE were on average 36 min and 0.8%less compared to pre-season and 42 min and 3.0%less compared to in-season training periods,respectively.Conclusion:Athletes’sleep duration was found to be short with low SE,in comparison to the general consensus for non-athlete healthy adults.Notable sleep issues were revealed in young athletes.Sleep quality and architecture tend to change across different training periods.

Twenty-four-hour movement guidelines during middle adolescence and their association with glucose outcomes and type 2 diabetes mellitus in adulthood

Purpose:The aim of the present study was to determine the association between adherence to the 24-h movement guidelines during middle adolescence and glucose outcomes(glycated hemoglobin and fasting glucose)and type 2 diabetes mellitus(T2DM)in adulthood,14 and 22 years later.Methods:We analyzed data from apparently healthy adolescents aged 12-18 years who participated in WavesⅠandⅡ(1994-1996,n=14,738),WaveⅣ(2008-2009,n=8913),and Wave V(2016-2018,n=3457)of the National Longitudinal Study of Adolescent to Adult Health(Add Health)in the United States.Physical activity,screen time,and sleep duration were measured using questionnaires,and the 24-h guidelines were defined as:5 or more times moderate-to-vigorous physical activity per week,≤2 h per day of screen time,and 9-11 h of sleep for 12-13 years and 8-10 h for 14-17 years.Capillary and venous whole blood was collected and analyzed to determine glycated hemoglobin and fasting glucose for WavesⅣandⅤ,respectively.Results:Only 2.1%of the adolescents met all the 3 guidelines,and 37.8%met none of them.In both wavesⅣandⅤ,adolescents who met physical activity and screen time guidelines had lower odds of T2DM in adulthood than those who did not meet any of these guidelines(WaveⅣ;prevalence ratio(PR)=0.57,95%confidence interval(95%CI):0.21-0.89;Wave V:PR=0.43,95%CI:0.32-0.74).Only for Wave V did adolescents who met all 3 guidelines have lower odds of T2DM at follow-up compared with those who did not meet any of these guidelines(PR=0.47,95%CI:0.24-0.91).Also,for each increase in meeting one of the 24-h recommendations,the odds of T2DM decreased by 18%(PR=0.82,95%CI:0.61-0.99)and 15%(PR=0.85,95%CI:0.65-0.98)in adulthood for WavesⅣandⅤ,respectively.Conclusion:Promoting all 24-h movement guidelines in adolescence,especially physical activity and screen time,is important for lowering the potential risk of T2DM in adulthood.

Meeting 24-h movement guidelines: Prevalence, correlates, and the relationships with overweight and obesity among Chinese children and adolescents

Background:Meeting 24-h movement guidelines by children and adolescents has been associated with improved indicators of health,although it has been under-studied in China.Hence,this study aimed to investigate the prevalence of meeting the 24-h movement guidelines,its correlates,and its relationships with body mass index in children and adolescents in China.Methods:Cross-sectional data from the 2017 Youth Study in China of 114,072 children and adolescents(mean age=13.75 years,49.18%boys)were used.Meeting 24-h movement guidelines(60 min of daily moderate-to-vigorous physical activity,2 h of daily leisure screen time,911 h and 810 h nightly sleep duration for 613-year-olds and 1417-year-olds,respectively)and height and weight of all participants were assessed.The prevalence of meeting the 24-h movement guidelines and World Health Organization weight status categories were determined.Generalized linear models were used to determine the correlates of meeting the 24-h movement guidelines and the relationships of meeting the 24-h movement guidelines with overweight(OW)and obesity(OB).Results:Only 5.12%of Chinese children and adolescents met the 24-h movement guidelines,and 22.44%were classified as OW/OB.Older children and adolescents were less likely to meet the 24-h movement guidelines.Parental education level and family income were positively related to meeting the 24-h movement guidelines.Children and adolescents meeting the 24-h movement guidelines showed lower odds ratios for OW/OB.Compared with participants meeting the 24-h movement guidelines,boys in 4th6th grades met none of the recommendations(OR=1.22,95%CI:1.061.40),met the screen time recommendation only(OR=1.13,95%CI:1.011.28),met the nightly sleep duration recommendation only(OR=1.14,95%CI:1.031.28),and had significantly higher odds ratios for OW/OB.Similar trends were observed for girls in 4th6th grades:meeting none of the guidelines(OR=1.35,95%CI:1.141.59),meeting sleep duration guidelines only(OR=1.23,95%CI:1.081.39),and meeting moderate-to-vigorous physical activity+nightly sleep duration guidelines(OR=1.24,95%CI:1.011.54).For girls in 7th9th grades,the following trend was observed:meeting none of the guidelines(OR=1.30,95%CI:1.011.67).Conclusion:Very few Chinese children and adolescents met the 24-h movement guidelines.Age(negatively correlated),parental education level,and family income(both positively correlated)were correlates of meeting the 24-h movement guidelines.Children and adolescents meeting the 24-h movement guidelines were more likely to have lower risks for OW/OB,especially in the youngest age group(Grades 46);and girls in the middle age group(Grades 79)were also more likely to have lower risks for OW/OB.Further research studies should explore additional correlates and determinants for meeting the 24-h movement guidelines.Also,future studies should use longitudinal or interventional designs to determine the relationships between meeting the 24-h movement guidelines and OW/OB and other health indicators,while taking sex and age differences into account.

Associations of Daytime Napping with Incident Cardiovascular Diseases and Hypertension in Chinese Adults:A Nationwide Cohort Study

Objective This study aimed to examine the associations of daytime napping with incident risks of cardiovascular diseases(CVDs)and hypertension(HTN).Methods Data for napping and CVD outcomes in 25 provinces were collected from baseline(2010)and three waves of follow-up(2012-2017)investigations of the China Family Panel Studies.Cox frailty models with random intercepts for the surveyed provinces were used to assess the longitudinal effects of daytime napping on CVD and HTN.Results Compared with non-nappers,30+min nappers had higher risks of CVD and HTN,while no significant associations were observed among<30 min nappers.Incident risks among 30-to<60-min nappers increased by 22%[hazard ratio(HR)1.22,95% confidence interval(CI)1.08-1.39]for CVD and 21%(1.21,1.04-1.41)for HTN,respectively,with corresponding HRs of CVD and HTN of 1.27(1.09-1.47)and 1.38(1.16-1.65)among≥60 min nappers.Nap-associated CVD risks varied by subgroups,with stronger associations in participants with lower body mass index(<24 kg/m^(2)),physically inactive persons,smokers,and participants with longer nighttime sleep(≥7 h/night).Significant effects of daytime napping were observed on rural and northern residents only,highlighting great regional variations in CVD risks associated with napping habits.Conclusions This cohort study revealed strong evidence that long daytime napping(≥30 min)is associated with an increased incidence of cardiovascular events.

The Impact of Sleep-Wake Behaviour on Tennis Match Performance in Junior State Grade Tennis Players

Purpose To date,no study has investigated the extent to which sleep-wake behaviour(SWB)influences match performance in junior tennis players.This study aimed to assess the influence of SWB for the week and night before on match performance,particularly match analytics and activity.Methods This study recruited 10 junior state grade tennis players who wore an actigraphy device and completed a sleep diary for the week before their match on two separate occasions throughout their competition season.Players wore a global positioning system device to track their movement during matches,and an experienced tennis coach recorded players'match analytics.Results This study showed that the sleep fragmentation index was significantly lower the week before matches in females who had won than those who had lost.Additionally,the sleep fragmentation index was significantly lower the night before a given match than the week before.Only sleep fragmentation index and sleep latency significantly influenced match performance in junior tennis players.The percentage of second serves points won differed between match wins and losses for male players,while winners and forced errors differed for female players.Conclusion These findings provide a detailed profile of tennis match play in junior state grade players.Despite individual differences,reduced restlessness the night before a match coincides with increased match performance.