Joint associations of physical activity and screen time with overweight among japanese adults

Independent and Combined Associations of Physical Activity and Screen Time With Biomarkers of Inflammation in Children and Adolescents With Overweight/Obesity

PURPOSE

Inflammation regulation is important for obesity management and prevention of obesity-related diseases. This cross-sectional study aimed to analyze the independent and combined associations of physical activity and screen time with biomarkers of inflammation in children and adolescents with overweight/obesity.

METHOD

A total of 1289 children and adolescents with overweight/obesity were included from the 2015 to 2018 National Health and Nutrition Examination Survey. Multivariable linear regressions were conducted for the association analyses.

RESULTS

For the independent associations, a negative dose-dependent relationship was demonstrated between physical activity and inflammatory biomarker high-sensitivity C-reactive protein (hsCRP) in adolescents with overweight/obesity (P < .001) but not children; screen time was not associated with hsCRP in both children and adolescents. No significant association was found between physical activity or screen time with other inflammatory biomarkers. For the combined associations, there was an interaction between physical activity and screen time on hsCRP in adolescents with overweight/obesity (P = .014). In addition, the negative association between physical activity and hsCRP was greater in boys compared with girls and in Hispanic and non-Hispanic Black individuals compared with non-Hispanic White individuals.

CONCLUSION

This study demonstrated a combined association of physical activity and screen time with inflammatory biomarker hsCRP in adolescents with overweight/obesity.

Dietary and Lifestyle Risk Factors of Obesity Among Young Adults: A Scoping Review of Observational Studies

PURPOSE OF REVIEW

Obesity is a growing public health concern worldwide, especially among young adults. This scoping review aims to identify and summarize the current evidence on dietary and lifestyle risk factors associated with obesity among young adults.

RECENT FINDINGS

A scoping review was performed using the PRISMA-ScR guidelines. A systematic search of five electronic databases published from inception to October 2023 was conducted. A total of 46 observational studies met the inclusion criteria and were included in the review. The findings suggest that high intake of energy-dense foods, unhealthy eating habits, poor sleep quality, and increased screen time were significant risk factors for obesity among young adults. In contrast, the association between obesity and sedentary behavior, low physical activity levels, alcohol consumption, and smoking habits was inconclusive. The reviewed evidence suggests that unhealthy dietary habits and lifestyle behaviors are associated with an increased risk of obesity among young adults. The findings highlight the need for further research on these modifiable risk factors to prevent and manage obesity among young adults.

Association of Physical Activity and Screen Time With Body Mass Index Among US Adolescents

IMPORTANCE

The Physical Activity Guidelines Advisory Committee Scientific Report identified important research gaps to inform future guidance for adolescents, including limited evidence on the importance of sedentary behaviors (screen time) and their interactions with physical activity for adolescent health outcomes, including overweight and obesity.

OBJECTIVE

To identify the independent associations of physical activity and screen time categories, and the interactions between physical activity and screen time categories, with body mass index (BMI) and overweight and obesity in adolescents.

DESIGN, SETTING, AND PARTICIPANTS

This cross-sectional study used data from the Adolescent Brain Cognitive Development (ABCD) Study collected from September 10, 2018, to September 29, 2020. Data were analyzed from July 8 to December 20, 2022. A total of 5797 adolescents aged 10 to 14 years from 21 racially and ethnically diverse study sites across the US were included in the analysis.

EXPOSURES

Categories of total step count per day (with 1000 to 6000 steps per day indicating low, >6000 to 12 000 steps per day indicating medium, and >12 000 steps per day indicating high), as measured by a wearable digital device (Fitbit), and categories of self-reported screen time hours per day (with 0 to 4 hours per day indicating low, >4 to 8 hours per day indicating medium, and >8 hours per day indicating high).

MAIN OUTCOMES AND MEASURES

Participant BMI was calculated as weight in kilograms divided by height in meters squared and converted into sex- and age-specific percentiles in accordance with the Centers for Disease Control and Prevention growth curves and definitions. Individuals were classified as having overweight or obesity if their BMI was in the 85th percentile or higher for sex and age.

RESULTS

Among 5797 adolescents included in the analytic sample, 50.4% were male, 61.0% were White, 35.0% had overweight or obesity, and the mean (SD) age was 12.0 (0.6) years. Mean (SD) reported screen time use was 6.5 (5.4) hours per day, and mean (SD) overall step count was 9246.6 (3111.3) steps per day. In models including both screen time and step count, medium (risk ratio [RR], 1.24; 95% CI, 1.12-1.37) and high (RR, 1.29; 95% CI, 1.16-1.44) screen time categories were associated with higher overweight or obesity risk compared with the low screen time category. Medium (RR, 1.19; 95% CI, 1.06-1.35) and low (RR, 1.30; 95% CI, 1.11-1.51) step count categories were associated with higher overweight or obesity risk compared with the high step count category. Evidence of effect modification between screen time and step count was observed for BMI percentile. For instance, among adolescents with low screen use, medium step count was associated with a 1.55 higher BMI percentile, and low step count was associated with a 7.48 higher BMI percentile. However, among those with high screen use, step count categories did not significantly change the association with higher BMI percentile (low step count: 8.79 higher BMI percentile; medium step count: 8.76 higher BMI percentile; high step count: 8.26 higher BMI percentile).

CONCLUSIONS AND RELEVANCE

In this cross-sectional study, a combination of low screen time and high step count was associated with lower BMI percentile in adolescents. These results suggest that high step count may not offset higher overweight or obesity risk for adolescents with high screen time, and low screen time may not offset higher overweight or obesity risk for adolescents with low step count. These findings addressed several research gaps identified by the Physical Activity Guidelines Advisory Committee Scientific Report and may be used to inform future screen time and physical activity guidance for adolescents.

Combination of physical activity and screen time on life satisfaction in adults: A cross-sectional survey

Background

Sufficient physical activity (PA) and limited screen time (ST) have been shown to be positively associated with a variety of mental health outcomes. It has been known that PA and ST are independently associated with life satisfaction. Whereas, little is known about the association between combinations of PA and ST with life satisfaction in adults. This study aimed to explore the associations between PA and ST (in insolation or combination) and life satisfaction in adults.

Methods

Data from the 2014 European Social Survey (ESS) round 7 consisting of 22 countries were analyzed in this study. In total, self-reported data from 40,185 adults were included in the final analysis. The self-administered method was used to collect demographic information, PA, ST, and life satisfaction. The prevalence of meeting PA guidelines (at least 150 min per week) and ST guidelines (no more than 3 h per day) was calculated according to Canadian 24-h Movement Guidelines for Adults.

Results

Adults who were engaged in sufficient PA and limited ST were more likely to report a higher level of life satisfaction. Meeting PA or ST guidelines was more likely to report higher life satisfaction scores [odds ratio (OR) = 1.31, 95% CI: 1.16–1.47]. Compared with not meeting any guidelines, those who met both PA and ST guidelines had a higher OR (OR = 1.55, 95% CI: 1.37–1.76).

Conclusion

This study found that participating PA while limiting ST concurrently was linked with better life satisfaction. Creating an active lifestyle is important to population’s well-being.

Association Between Time Spent on Electronic Devices and Body Mass Index in Young Adults

Objective

To evaluate the association between time spent on electronic devices (TSED) and body mass index in young adults.

Methods

This cross-sectional study was conducted from June to December 2021 on 1877 students (aged 18–22 yrs) from multiple health Colleges of Imam Abdulrahman Bin Faisal University. The main tools of the study were 1) Body mass index (BMI) and an online questionnaire. The subjects were categorized into 3 main groups based on their TSED: 1) Low TSED < 2 hours/day, 2) Medium TSED= 3 to 5 hours/day, 3) Excessive TSED ≥ 6 hours /day. Based on BMI, subjects were categorized into three main groups: Normal and underweight (BMI ≤ 24.9), overweight (BMI > 25–29.9), and obese (BMI > 30).

Results

Participants’ average age was 20 ± 2 years. The average BMI was 23.5 k/m². The % of students falling into the categories of normal weight, overweight, and obesity was 69.2%, 19.05%, and 11.7% respectively. The average TSED of study participants was 8.2 ± 3.45 hrs /24 hours. 71.15% of participants indicated a TSED of ≥6 hrs/24 hours and 23.71% reported a TSED of 3–5 hrs/24 hours. Only 3.15% of participants reported TSED of ≤2 hrs/24 hours. Although a rise in the mean BMI was observed with an increase in the TSED, but this difference was not statistically significant. The pairwise wise comparison also failed to demonstrate any difference in BMI between different categories of TSED. Furthermore, no significant positive correlation was found between increased BMI and excessive TSED (P = 0.37).

Conclusion

A high percentage of young adults (31.2%) were overweight or obese, but excessive TSED was not significantly associated with increased BMI in this study population. Further studies are recommended to identify the effects of other factors in causing increased BMI in young adults.

Associations of changes in physical activity and discretionary screen time with incident obesity and adiposity changes: longitudinal findings from the UK Biobank

BACKGROUND

Physical activity (PA) and discretionary screen time (DST; television and computer use during leisure) are both associated with obesity risk, but little longitudinal evidence exists on their combined influence. This study examined the independent and joint associations of changes in PA and DST with incident obesity, body mass index (BMI) and waist circumference (WC).

METHODS

We analysed the data of individuals aged 40-69 years from the UK Biobank, a large-scale, population-based prospective cohort study. PA was measured using the International Physical Activity Questionnaire and DST was defined as the total of daily TV viewing and non-occupational computer use. Changes in PA and DST over time were defined using departure from sex-specific baseline tertiles and categorised as worsened (PA decreased/DST increased), maintained, and improved (PA increased/DST decreased). We then used each exposure change to define a joint PA-DST change variable with nine mutually exclusive groups. We used multivariable adjusted mixed-effects linear and Poisson models to examine the independent and joint associations between PA and DST changes with BMI and WC and incident obesity, respectively. Development of a BMI ≥ 30 kg/m² was defined as incident obesity.

RESULTS

Among 30,735 participants, 1,628 (5.3%) developed incident obesity over a mean follow-up of 6.9 (2.2) years. In the independent association analyses, improving PA (Incident Rate Ratio (IRR) 0.46 (0.38-0.56)) was associated with a lower risk of incident obesity than maintaining PA, maintaining DST, or improving DST. Compared to the referent group (both PA and DST worsened), all other combinations of PA and DST changes were associated with lower incident obesity risk in the joint association analyses. We observed substantial beneficial associations in the improved PA groups, regardless of DST change [e.g., DST worsened (IRR 0.31 (0.21-0.44)), maintained (IRR 0.34 (0.25-0.46)), or improved (IRR 0.35 (0.22-0.56)]. The most pronounced decline in BMI and WC was observed when PA was maintained or improved and DST was maintained.

CONCLUSION

We found that improved PA had the most pronounced beneficial associations with incident obesity, irrespective of DST changes. Improvements in PA or DST mutually attenuated the deleterious effects of the other behaviour's deterioration.

Combined Physical Activity and Sitting Time Association on Older Adults' Body Mass Index: Cross-Sectional Findings From the Brazilian Longitudinal Study of Aging

This study examined isolated and combined associations of physical activity (PA) and sitting time (ST) with body mass index (BMI) among older Brazilian adults. We have analyzed baseline data of 8,177 participants aged 50 years and older from the Brazilian Longitudinal Study of Aging. Respondents were categorized into sufficient PA/low ST, sufficient PA/high ST, insufficient PA/low ST, or insufficient PA/high ST using the Short Version of International Physical Activity Questionnaire. Multinomial logistic regression analysis examined the associations of being underweight (BMI, <18 kg/m2), overweight (BMI, 25-29.9 kg/m2), and obese (BMI, ≥30 kg/m2) with PA and ST categories. High ST (≥165 min/day) was associated with overweight (odds ratio, 1.26; 95% confidence interval [1.11, 1.44]) and obesity (odds ratio, 1.43; 95% confidence interval [1.21, 1.70]). However, no association was observed between PA and BMI. Participants in the insufficient and sufficient PA/high ST categories were more likely to be obese after adjusting for sociodemographic and health condition. Our findings call for public health initiatives that consider reducing ST in older adults.

Factors associated with body image dissatisfaction in adults: a cross-sectional analysis of the ELSA-Brasil Study

The aim of this article is to assess the association between body image dissatisfaction and sociodemographic and health behaviors, according to sex. Data were analyzed for 6,289 women and 5,188 men (35-59 years), participants in the baseline of the Longitudinal Study of Adult Health (ELSA-Brasil), using multinomial regression. The odds of dissatisfaction due to feeling underweight were higher among in women with low schooling and those who only consumed fruit weekly. Moderate physical activity reduced this type of dissatisfaction by 50%. Higher odds of dissatisfaction due to overweight were seen in married women, those who practiced light physical activity, and former smokers. Men with secondary schooling and excessive alcohol consumption showed 50% higher odds of dissatisfaction due to underweight, while light or moderate physical activity increased the odds by 75% and 94%, respectively. Among men, light and moderate physical activity were also associated with increased odds of dissatisfaction due to overweight. These findings corroborate that unhealthy habits and behaviors can influence body image dissatisfaction with different patterns between women and men.

Novel Equations to Estimate Resting Energy Expenditure during Sitting and Sleeping

INTRODUCTION

Young and early middle-aged office workers spend most of the day sitting or sleeping. Few studies have used a metabolic chamber to report sitting resting energy expenditure (REE) or sleeping metabolic rate (SMR) estimation equations. This study aimed to develop novel equations for estimating sitting REE and SMR, and previously published equations for SMR were compared against measured values.

METHODS

The relationships among sitting REE, SMR, and body composition measured in clinical trials were analyzed. The body composition (fat-free mass [FFM] and fat mass) and energy metabolism of 85 healthy young and early middle-aged Japanese individuals were measured using dual-energy X-ray absorptiometry and a metabolic chamber, respectively. Novel estimate equations were developed using stepwise multiple regression analysis. Estimates of SMR using a new equation and 2 published equations were compared against measured SMR.

RESULTS

The sitting mREE and mSMR were highly correlated (r = 0.756, p < 0.01). The new FFM-based estimate accounted for 50.4% of the variance in measured sitting REE (mREE) and 82.3% of the variance in measured SMR (mSMR). The new body weight-based estimate accounted for 49.3% of the variance in sitting mREE and 82.2% of the variance in mSMR. Compared with mSMR, the SMR estimate using an FFM-based published equation was slightly underestimated.

CONCLUSION

These novel body weight- and FFM-based equations may help estimate sitting REE and SMR in young and early middle-aged adults. Previous SMR estimated FFM-based equations were slightly underestimated against measured SMR; however, we confirmed the previous SMR estimate equations could be useful. This finding suggests that sitting REE and SMR can be easily estimated from individual characteristics and applied in clinical settings.

Independent and combined associations between screen time and physical activity and perceived stress among college students

Although both screen time (ST) and physical activity (PA) are associated with stress, independent and combined associations between ST and PA, and perceived stress among college students, have remained unclear. The present study included 1137 undergraduate medical students from a university in Shenyang, Northeast China. PA and perceived stress were measured using the International Physical Activity Questionnaire (IPAQ)-Long Form and the Chinese Perceived Stress Scale (CPSS), respectively. ST and students' characteristics were determined using a self-administered questionnaire. Data were analyzed using the independent t-test, Pearson Chi-squared test, and logistic regression. After adjusting for potential confounding factors, females reporting high ST (HST, ST > 6 h/day) were more likely to experience stress than those reporting low ST (LST, ST ≤ 6 h/day) (OR = 1.557), while those reporting light- and moderate-intensity PA (LMPA) were more likely to experience stress than those reporting vigorous-intensity PA (VIPA) (OR = 1.674). Analysis of the combined effects of PA and ST showed that, among female students, those reporting both LST and LMPA (OR = 2.174), both HST and VIPA (OR = 2.088), and both HST and LMPA (OR = 2.797) were more likely to experience stress compared to those reporting both LST and VIPA (the reference category). The present study confirmed that LST and VIPA were independently and concurrently associated with significantly lower stress among college students, suggesting that promoting PA and reducing ST might be an effective way to reduce perceived stress among college students.

Association between psychological distress and elevated use of electronic devices among U.S. adolescents: Results from the youth risk behavior surveillance 2009-2017

OBJECTIVE

The purpose of this study was to provide updated information about the prevalence and temporal trends of elevated use of electronic devices (EUED) in leisure time (i.e., 3 h or more on an average school day) in nationally representative samples of U.S. adolescents in recent years and to determine whether there is a significant association between EUED and psychological distress.

METHODS

We used the national Youth Risk Behavior Survey (YRBS) data from 2009, 2011, 2013, 2015, and 2017 (N = 75,807). Propensity score matching was used to reduce selection bias due to potential confounding factors with EUED. Ordinal logistic regression analyses were performed for the matched samples to predict the association between EUED and psychological distress.

RESULTS

The prevalence of EUED in U.S. youth has substantially increased from 24.9% in 2009 to 43.1% in 2017 (p < .001). Boys had higher rates of EUED than girls only in 2009 and 2011 but not in 2013, 2015, and 2017. A significant association between EUED and psychological distress was identified throughout all the five survey years. The odds of having a higher level of psychological distress increased approximately 1.5 times among youth with EUED than those without.

CONCLUSIONS

The prevalence of U.S. youth with psychological distress and EUED has increased simultaneously in the past several years. Future longitudinal studies are warranted to examine causal and/or reciprocal relationship between the two.

Revisiting Factors Associated With Screen Time Media Use: A Structural Study Among School-Aged Adolescents

BACKGROUND

Screen-based media overuse has been related to harmful consequences especially among children and adolescents. Given their complex interrelationships, predictors of screen time (ST) should be analyzed simultaneously rather than individually to avoid incomplete conclusions.

METHODS

Structural equation models were conducted to examine associations between media ST (television, video games, and computers) along with harmful consequences in adolescents' well-being, such as underweight and overweight, depression, and school failure. Predictors included individual (gender, age, and physical activity), family (structure and socioeconomic background), and substance use variables. We used the Health Behaviour in School-aged Children survey organized in 2014, including eighth- and ninth-grade students living in France (N = 3720).

RESULTS

Students reported spending 3 hours per day in front of each media. Spending more than 2 hours behind each of those 3 media was associated with lower life satisfaction, less physical activity, active school bullying, and grade repetition. Socioeconomic status was the most important predictor of ST, whereas regular substance uses showed modest associations.

CONCLUSION

The main implication of our findings is to sensitize parents and stakeholders about the limitation of ST, including their own use that adolescents are likely to mimic. Alternative measures such as off-line time should be encouraged.

General and Abdominal Obesity Is Related to Physical Activity, Smoking and Sleeping Behaviours and Mediated by the Educational Level: Findings from the ANIBES Study in Spain

The aim of the present study was to analyze the association of socioeconomic (SES) and lifestyle factors, with the conditions of overweight (OW), general (OB) and abdominal obesity (AO) in Spanish adults. A representative sample of 1655 Spanish adults (18 to 65 years) from the ANIBES Study was investigated. Collected data included measured anthropometry (weight, height and waist circumference), demographic and SES data (region and habitant population size, educational level, family income, unemployment rate), physical activity (PA) and other lifestyle factors (sleeping time and frequency of viewing television). OW, OB and AO were determined in each participant. Being male, older than 40 years, and watching television more frequently were associated with higher risk of OB and AO, whereas those with a higher level of education, smokers, and more time in sleeping and in vigorous PA, but not in moderate-vigorous PA, were associated with a lower risk. Living in the Atlantic region and stating no answer to the question regarding family income were also associated with lower risk of AO. Strategies for preventing and reducing OB and AO should consider improving sleeping habits and PA. They should also pay more attention to the most vulnerable groups such as those less educated.

Physical Activity, Television Viewing Time, and 12-Year Changes in Waist Circumference

Purpose

Both moderate-to-vigorous physical activity (MVPA) and sedentary behavior can be associated with adult adiposity. Much of the relevant evidence is from cross-sectional studies or from prospective studies with relevant exposure measures at a single time point before weight gain or incident obesity. This study examined whether changes in MVPA and television (TV) viewing time are associated with subsequent changes in waist circumference, using data from three separate observation points in a large population-based prospective study of Australian adults.

Methods

Data were obtained from the Australian Diabetes, Obesity, and Lifestyle study collected in 1999–2000 (baseline), 2004–2005 (wave 2), and 2011–2012 (wave 3). The study sample consisted of adults age 25 to 74 yr at baseline who also attended site measurement at three time points (n = 3261). Multilevel linear regression analysis examined associations of initial 5-yr changes in MVPA and TV viewing time (from baseline to wave 2) with 12-yr change in waist circumference (from baseline to wave 3), adjusting for well-known confounders.

Results

As categorical predictors, increases in MVPA significantly attenuated increases in waist circumference (P for trend < 0.001). TV viewing time change was not significantly associated with changes in waist circumference (P for trend = 0.06). Combined categories of MVPA and TV viewing time changes were predictive of waist circumference increases; compared with those who increased MVPA and reduced TV viewing time, those who reduced MVPA and increased TV viewing time had a 2-cm greater increase in waist circumference (P = 0.001).

Conclusion

Decreasing MVPA emerged as a significant predictor of increases in waist circumference. Increasing TV viewing time was also influential, but its impact was much weaker than MVPA.

Objectively measured sedentary behavior and moderate-to-vigorous physical activity on the health-related quality of life in US adults: The National Health and Nutrition Examination Survey 2003-2006

BACKGROUND

Health-related quality of life (HRQOL) represents an individual's perception of physical, mental, and social well-being and is a strong predictor of health status. Few studies have examined associations of sedentary behavior (SB) and moderate-to-vigorous physical activity (MVPA) with HRQOL in the general population.

PURPOSE

This study aimed to determine combined associations of objectively measured SB and MVPA on the risk of poor HRQOL in the general US population, after controlling for potential confounding factors.

METHODS

We analyzed data from 5359 adults from the National Health and Nutrition Examination Survey 2003-2006. HRQOL was measured using a HRQOL-4 consisting of four questions focused on the self-perception of general health, physical health, mental health, and activity limitation. We dichotomized each HRQOL-4 component as good versus poor and defined poor overall HRQOL when participants had any poor HRQOL components. SB and MVPA were measured using an accelerometer. Survey logistic models were examined to estimate the odds ratio (OR) and 95% confidence interval (CI) for poor HRQOL by SB and MVPA as tertiles.

RESULTS

When examined as a combination of SB and MVPA, a substantial decrease in the risk of poor overall HRQOL was found in individuals with low SB/high MVPA [OR 0.69 (95% CI 0.51-0.94) and moderate SB/high MVPA (OR 0.56 (95% CI 0.40-0.78)], but no significant decrease was found in individuals with high SB/high MVPA (vs. high SB/low MVPA).

CONCLUSION

Our findings suggest that both increasing MVPA and reducing time spent in SB may be useful strategies to improve HRQOL.

Joint association of screen time and physical activity on self-rated health and life satisfaction in children and adolescents: the CASPIAN-IV study

BACKGROUND

Self-rated health and life satisfaction are two subjective measures for assessing overall health status. This study aims to investigate the association of self-rated health and life satisfaction with physical activity and screen time.

METHODS

As part of the fourth survey of a national surveillance program in Iran (CASPIAN-IV study), 14 880 students aged 6 to 18 years were selected via multi-stage cluster sampling from 30 provinces. Data were obtained from the WHO Global School-Based Student Health Survey questionnaire.

RESULTS

A total of 13 486 students with mean age of 12.47 (SD 3.36) completed the study. In crude model both prolonged screen time and physical activity were associated with favorable life satisfaction and self-rated health. However, in multivariate analysis only high physical activity was associated with good self-rated health (OR 1.37) and life satisfaction (OR 1.39), while prolonged screen time was not associated with good self-rated health (OR 1.02) and life satisfaction (OR 0.94). For combined screen time-physical activity variable, low screen time-high physical activity combination had the highest OR for both good self-rated health (OR 1.37) and life satisfaction (OR 1.43) in multivariate analysis.

CONCLUSIONS

Our findings suggest that increasing physical activity is more crucial than emphasizing reducing screen time in improving the well-being of children and adolescents.

Joint Association of Screen Time and Physical Activity with Cardiometabolic Risk Factors in a National Sample of Iranian Adolescents: The CASPIANIII Study

Metabolic syndrome (MetS) and its contributing factors are considered important health problems in the pediatric age group. This study was designed to assess the joint association of ST and PA with cardiometabolic risk factors among Iranian adolescents. A representative sample of 5625 (50.2% boys) school students with a mean age of 14.73 (SD: 2.41) were selected through multistage random cluster sampling method from urban and rural areas of 27 provinces in Iran. ST and PA were assessed by self-administered validated questionnaires. Anthropometric measures (height, weight and waist circumference (WC)) and MetS components (abdominal obesity, elevated blood pressure (BP), low high-density lipoprotein cholesterol (HDL-C), elevated triglycerides (TG) and high fasting blood sugar (FBG)) were measured according to standardized protocols. MetS was defined according to the Adult Treatment Panel III criteria modified for the pediatric age group. Moreover, elevated total cholesterol (TC), elevated low-density lipoprotein cholesterol (LDL-C), and generalized obesity were considered as other cardiometabolic risk factors. Students with high ST levels had significantly higher body mass index z-score (BMI z-score), WC, TG, LDL-C, and BP as well as lower HDL-C level; whereas those with high PA levels had significantly higher HDL-C levels as well as lower BMI z-score, TC, and BP. Adolescents with low PA/ high ST levels had significantly higher BMI, WC, LDL-C levels, as well as higher SBP and DBP compared to their other counterparts. In Multivariate model, joint effect of low PA/ high ST (compared to the high PA/low ST group) increased the odds of overweight, abdominal obesity and low HDL-C and decreased the odds of elevated TC. The findings of this study showed that joint association of high ST and low PA have direct association with abdominal obesity, overweight and low HDL-C and indirect association with elevated TC.

Body Image and Nutritional Status Are Associated with Physical Activity in Men and Women: The ELSA-Brasil Study

The association of body image dissatisfaction and obesity with physical activity is likely to differ according to gender. To investigate this hypothesis, we conducted a cross-sectional study among the ELSA-Brasil cohort members aged 34-65 years (n=13,286). The body image dissatisfaction was present even among normal weight individuals of both sexes and was associated with lesser chances of practicing moderate physical activity in women and intense physical activity in men. Men and women with central obesity were less prone to practice physical activity of high or moderate intensity. Overweight and obese men were more likely to report vigorous physical activity while obese women were less likely to report this level of physical activity. Body images as well as nutritional status are related to physical activity in both sexes, but the association with physical activity differs by gender.

Lack of exercise of "moderate to vigorous" intensity in people with low levels of physical activity is a major discriminant for sociodemographic factors and morbidity

INTRODUCTION

The aim is to examine the differences between participation at low and zero moderate to vigorous physical activity (MVPA) in relation to their trends and associations with known socio-demographic and health factors. We hypothesised that the number of people at zero MVPA level could be rising despite a parallel increase in the population meeting the recommended MVPA level. We also hypothesised that graded associations of sociodemographic and health factors exist across MVPA levels.

METHODS

Two independent population-based samples (n = 4320 [2004] and n = 2176 [1997]), were recruited with a stratified and random sampling procedure and interviewed at home by professional interviewers. The MVPA was assessed by validated questionnaire. The participants were classified into three MVPA levels: zero, low and recommended MVPA. The trend of each MVPA level was analysed with the standardized prevalence ratios. Correlates of low and zero MVPA levels were examined using multinomial logistic regression.

RESULTS

The population at zero and recommended MVPA levels rose between 1997-2004 by 12% (95% CI, 5-20%) and 7% (95% CI,-4-19%) respectively, while the population at low MVPA level decreased. At zero MVPA level, associative patterns were observed with sociodemographic and health factors which were different when compared to the population at low MVPA level.

CONCLUSIONS

Despite the slight increase of population meeting the recommended MVPA level, a higher trend of increase was observed at zero MVPA level. Both recommended and low MPVA levels increased their participation by absorbing participants from the low MVPA level. The sociodemographic profile of those with low MVPA was more similar to the population at recommended MVPA than at zero MVPA level. Methodological implications about the combination of light and moderate-intensity PA could be derived. The prevention of decline in actual low MVPA could change the trend of increase in the population at zero MVPA level, particularly among young adults.

Combined effect of physical activity and leisure time sitting on long-term risk of incident obesity and metabolic risk factor clustering

AIMS/HYPOTHESIS

Our study aimed to investigate the combined effects of moderate-to-vigorous physical activity and leisure time sitting on the long-term risk of obesity and clustering of metabolic risk factors.

METHODS

The duration of moderate and vigorous physical activity and of leisure time sitting was assessed by questionnaire between 1997 and 1999 among 3,670 participants from the Whitehall II cohort study (73% male; mean age 56 years). Multivariable-adjusted logistic regression models examined associations of physical activity and leisure time sitting tertiles with odds of incident obesity (BMI ≥ 30 kg/m(2)) and incident metabolic risk factor clustering (two or more of the following: low HDL-cholesterol, high triacylglycerol, hypertension, hyperglycaemia, insulin resistance) at 5 and 10 year follow-ups.

RESULTS

Physical activity, but not leisure time sitting, was associated with incident obesity. The lowest odds of incident obesity after 5 years were observed for individuals reporting both high physical activity and low leisure time sitting (OR = 0.26; 95% CI 0.11, 0.64), with weaker effects after 10 years. Compared with individuals in the low physical activity/high leisure time sitting group, those with intermediate levels of both physical activity and leisure time sitting had lower odds of incident metabolic risk factor clustering after 5 years (OR 0.53; 95% CI 0.36, 0.78), with similar odds after 10 years.

CONCLUSIONS/INTERPRETATION

Both high levels of physical activity and low levels of leisure time sitting may be required to substantially reduce the risk of obesity. Associations with developing metabolic risk factor clustering were less clear.

The independent and combined associations of physical activity and sedentary behavior with obesity in adults: NHANES 2003-06

OBJECTIVE

To examine the combined influence of moderate-to-vigorous physical activity (MVPA) and sedentary behavior on obesity in US adults.

DESIGN AND METHODS

Cross-sectional analyses were undertaken on a nationally representative sample of 5,083 adults from the April 2003 and June 2005 National Health and Nutrition Examination Survey. Self-reported TV time was divided into low, moderate, and high categories. Accelerometer-derived total sedentary and MVPA minutes divided into low, moderate, and high tertiles. The independent associations between MVPA, TV, and total sedentary time and obesity were examined using logistic regression. Participants were then cross tabulated into nine MVPA-sedentary behavior groups, and logistic regression was used to examine the combined influence of MVPA and sedentary behavior on the odds of being obese.

RESULTS

MVPA was consistently inversely associated with obesity, regardless of sedentary behavior [odds ratio (OR) = 1.80-4.00]. There were inconsistent positive associations between TV time and risk of obesity in men, but not between total sedentary time and risk of obesity in either men or women.

CONCLUSIONS

Obesity was more strongly related to MVPA than either TV time or total sedentary time in US adults. Small differences in daily MVPA (5-10 min) were associated with relatively large differences in risk of obesity.

Joint association of sitting time and physical activity with metabolic risk factors among middle-aged Malays in a developing country: a cross-sectional study

Background

Prolonged sitting is associated with increased weight and higher risks for abdominal obesity, dyslipidaemia, hyperglycaemia and hypertension among the adult population. This has been well documented in the West, but studies on these associations are lacking in developing countries, including Malaysia.

Objective

This cross-sectional study aimed to examine the joint association of sitting time and physical activity with metabolic risk factors among middle-aged working adults.

Methodology

A total of 686 Malay men and women participated (mean age 45.9±6.5 years). Metabolic syndrome was diagnosed from the modified NCEP ATP III criteria. Self-reported sitting time was obtained with the validated Malay version of the International Physical Activity Questionnaire. Participants were asked about their time spent sitting during travel in a motor vehicle, e.g., car, motorcycle or bus, over the preceding 7 days. Logistic regression was used to estimate the odds ratio with the confidence interval for the combined effects of sitting quartiles and physical activity categories with metabolic risk factors.

Results/Significance

The prevalence of metabolic syndrome among our participants was 31.9%. Their average total sitting time (including transportation) was 7.6±2.4 h/day. After we adjusted for gender and educational level, higher sitting quartiles and physically inactive groups were associated with higher odds for metabolic syndrome compared with the referent group (sitting <6 h/day and physically active). In the physically active stratum, the odds for metabolic syndrome in participants who sat ≥9.3 h/day was 3.8 times that of participants who sat <6 h/day. Both higher sitting quartiles and insufficient physical activity were associated with adverse effects on abdominal obesity, hypertriglyceridemia and hyperglycaemia.

Conclusion

In joint analyses of sitting time and physical activity, higher sitting time and insufficient physical activity were deleteriously associated with odds for metabolic risk factors in middle-aged Malay men and women.