Associations between accelerometry measured physical activity and sedentary time and the metabolic syndrome: A meta-analysis of more than 6000 children and adolescents

Pace of life and perceived stress in international students

An accelerated pace of life greatly impacts individuals' health and lifestyles. However, this imposition has not been systematically researched within a culturally diverse sample. Thus, this study aimed to explore the subjective experience of the pace of life and its correlates in a culturally diverse sample within a German university context. This was done to test whether students (N = 156) with a migration background from other countries (n = 105) differ from students without migration background (n = 51). The pace of life, life satisfaction, stress, work-life balance, and health were measured on an individual level along with sociodemographic variables through online questionnaires. The pace of life was found to be invariant across students from different cultural backgrounds and unrelated to the length of stay at the current university. Interrelations were found between pace of life and work-life balance, r = .21, p < .05. While this study revealed perceived stress to be generally prevalent among students, the relationship between a slower pace of life and increased stress levels, ß = -.17, p < .05, disappears when controlling for health, ß = -.26, p < .01, work-life balance, ß = -.28, p < .01, and life satisfaction, ß = -.25, p < .01, as well as sociodemographic variables (only gender and medium length of stay were significant.) Furthermore, a mediation effect, b = -1.89, 95% CI [-3.598, -0.463], revealed that students cope with a faster pace of life by effective time management, which also leads to better work-life balance and in turn reduces the experienced level of stress. Future research should examine psychological mechanisms more extensively in longitudinal research and apply interventional designs to help students prevent and manage stress in the era of a fast-paced life.

Associations between metabolic syndrome and four heavy metals: A systematic review and meta-analysis

Four most concerned heavy metal pollutants, arsenic, cadmium, lead, and mercury may share common mechanisms to induce metabolic syndrome (MetS). However, recent studies exploring the relationships between MetS and metal exposure presented inconsistent findings. We aimed to clarify the relationship between heavy metal exposure biomarkers and MetS using a meta-analysis and systematic review approach. Literature search was conducted in international and the Chinese national databases up to June 2020. Of selected studies, we extracted the relevant data and evaluated the quality of each study's methodology. We then calculated the pooled effect sizes (ESs), standardized mean differences (SMDs), and their 95% confidence intervals (CIs) using a random-effect meta-analysis approach followed by stratification analyses for control of potential confounders. Involving 55,536 participants, the included 22 articles covered 52 observational studies reporting ESs and/or metal concentrations on specific metal and gender. Our results show that participants with MetS had significantly higher levels of heavy metal exposure [pooled ES = 1.16, 95% CI: 1.09, 1.23; n = 42, heterogeneity I2 = 75.6%; and SMD = 0.22, 95% CI: 0.15, 0.29; n = 32, I2 = 94.2%] than those without MetS. Pooled ESs in the subgroups stratified by arsenic, cadmium, lead, and mercury were 1.04 (95% CI: 0.97, 1.10; n = 8, I2 = 61.0%), 1.10 (0.95, 1.27; 11, 45.0%), 1.21 (1.00, 1.48; 12, 82.9%), and 1.26 (1.06, 1.48; 11, 67.7%), respectively. Pooled ESs in the subgroups stratified by blood, urine, and the other specimen were 1.22 (95% CI: 1.08, 1.38; n = 26, I2 = 75.8%), 1.06 (1.00, 1.13; 14, 58.1%), and 2.41 (1.30, 4.43; 2, 0.0%), respectively. In conclusion, heavy metal exposure was positively associated with MetS. Further studies are warranted to examine the effects of individual metals and their interaction on the relationship between MetS and heavy metals.

Bidirectional Day-to-Day Associations of Reported Sleep Duration With Accelerometer Measured Physical Activity and Sedentary Time Among Dutch Adolescents: An Observational Study

OBJECTIVES

To examine the bidirectional association of sleep duration with proportions of time spent in physical behaviors among Dutch adolescents.

METHODS

Adolescents (n = 294, 11-15 years) completed sleep diaries and wore an accelerometer (ActiGraph) over 1 week. With linear mixed-effects models, the authors estimated the association of sleep categories (short, optimal, and long) with the following day's proportion in physical behaviors. With generalized linear mixed models with binomial distribution, the authors estimated the association of physical behavior proportions on sleep categories. Physical behavior proportions were operationalized using percentages of wearing time and by applying a compositional approach. All analyses were stratified by gender accounting for differing developmental stages.

RESULTS

For males (number of observed days: 345, n = 83), short as compared with optimal sleep was associated with the following day's proportion spent in sedentary (-2.57%, p = .03, 95% confidence interval [CI] [-4.95, -0.19]) and light-intensity activities (1.96%, p = .02, 95% CI [0.27, 3.65]), which was not significant in the compositional approach models. Among females (number of observed days: 427, n = 104), long sleep was associated with the proportions spent in moderate- to vigorous-intensity physical activity (1.69%, p < .001, 95% CI [0.75, 2.64]) and in sedentary behavior (-3.02%, p < .01, 95% CI [-5.09, -0.96]), which was replicated by the compositional approach models. None of the associations between daytime activity and sleep were significant (number of obs.: 844, n = 204).

CONCLUSIONS

Results indicate partial associations between sleep and the following day's physical behaviors, and no associations between physical behaviors and the following night's sleep.

Comparison of ActiGraph GT9X Link with two Japanese accelerometers for assessments of free-living physical activity in junior high school students

Objective

This study compared the measurements of total steps and moderate-to-vigorous physical activity (MVPA) between ActiGraph and the Lifecorder and Active Style Pro accelerometers in junior high school students.

Results

The total steps and MVPA significantly differed between ActiGraph and Lifecorder measurements, whereas the intraclass correlation coefficients (ICCs) for total steps and MVPA between the two accelerometers were not significant. There was no significant difference between the total steps measured using ActiGraph and Active Style Pro, and moderate agreement was noted. Additionally, MVPA measured using ActiGraph and Active Style Pro significantly differed, whereas the ICC for MVPA measured using the two accelerometers was not significant. When comparing the total steps between ActiGraph and Lifecorder and MVPA between ActiGraph and Lifecorder or Active Style Pro, it should be noted that the accelerometer measurements are not compatible.

Associations between accelerometry measured physical activity and sedentary time and the metabolic syndrome: A meta-analysis of more than 6000 children and adolescents

BACKGROUND

Metabolic syndrome is increasingly prevalent in the pediatric population. To prevent an early onset, knowledge about its association with modifiable lifestyle factors is needed.

OBJECTIVES

To estimate the prevalence of the metabolic syndrome and examine its cross-sectional associations with physical activity and sedentary time.

METHODS

Participants were 6009 children and adolescents from 8 studies of the International Children's Accelerometry Database. Physical activity and sedentary time were measured by accelerometer. Metabolic syndrome was defined based on International Diabetes Federation criteria. Logistic regression models adjusted for sex, age and monitor wear time were used to examine the associations between physical activity, sedentary time and the metabolic syndrome in each study and effect estimates were combined using random-effects meta-analysis.

RESULTS

The overall prevalence of the metabolic syndrome was 2.9%. In crude models, a 10 min increase in moderate-to-vigorous intensity physical activity and vigorous-intensity physical activity were inversely associated with the metabolic syndrome [OR 0.88, 95% CI 0.82-0.94, OR 0.80, 95% CI 0.70-0.92]. One hour increase in sedentary time was positively associated with the metabolic syndrome [OR 1.28, 95% CI 1.13-1.45]. After adjustment for sedentary time, the association between moderate-to-vigorous-intensity physical activity and the metabolic syndrome remained significant [OR 0.91, 95% CI 0.84-0.99]. Sedentary time was not associated with the metabolic syndrome after adjustment for moderate-to-vigorous intensity physical activity [OR 1.14 95% CI 0.96-1.36].

CONCLUSIONS

Physical activity of at least moderate intensity but not sedentary time is independently associated with the metabolic syndrome.