Physical activity fluctuations and body fat during adolescence

Effect of baseline physical activity on the fat gain of adolescents in a 5-year cohort study in Ho Chi Minh City, Viet Nam

Differences in physical activity (PA) might lead to long-term weight control. Studies on inverse relations between PA and changes in fatness among adolescents are limited. This paper examined the effect of PA on adolescents' changing body fatness over 5 years in Ho Chi Minh City (HCMC). Two hundred thirty-five boys and 247 girls who have had skinfold thickness measurements in the baseline survey in 2004 were selected to follow yearly. We estimated PA as the average number of accelerometers' counts/h. Slopes of triceps, sub-scapular skinfolds and BMI were calculated and classified as increasing or stable/decreasing. To assess the effects of the low level of activity (i.e. below the median of the average number of counts) on the fat gain (i.e. increasing slopes), relative risk and 95 % CI were estimated using Poisson regression. The average number of counts/h in boys (7·8) was significantly higher than that in girls (5·0) (P < 0·001). On average, active girls still gained 0·51 mm in triceps skinfold (TSF) over 5 years, while active boys lost 0·12 mm. After controlling for baseline energy intake, baseline triceps and baseline age, inactive adolescents were 1·39 times higher than active ones to increase the slope of triceps (95 % CI 1·19, 1·63). The risk ratio was 1·62 for those with more body fat at baseline. In general, inactive students gained substantially more subcutaneous fat, especially in their TSF, than more active ones. Thus, strategies to prevent adolescent obesity in HCMC should consider the important role of PA to control this problem in adolescents effectively.

Teenage Sport Trajectory Is Associated With Physical Activity, but Not Body Composition or Blood Pressure in Early Adulthood

PURPOSE

Commonly held hypotheses in practice suggest that compared to single-sport participation, multi-sport participation is associated with higher physical activity (PA) levels and health benefits in the long term. To verify this in the general population, we identified sport participation trajectories during adolescence and examined their associations with PA and health outcomes in young adulthood.

METHODS

Participants (n = 655) from the Nicotine Dependence in Teens study self-reported sport involvement up to four times per year from age 12 to 17 years. At age 24, PA was assessed using questionnaires and accelerometers, and body composition (i.e., body mass index, waist circumference, skinfold thickness) and blood pressure were measured objectively. We used group-based trajectory modeling to identify sport participation trajectories from age 12 to 17. Associations between trajectories and outcomes in early adulthood were estimated in multivariable linear regression models.

RESULTS

We identified four sport participation trajectories during adolescence: non-participants (n = 148, 22%), dropouts (n = 133, 21%), single-sport (n = 248, 37%), and multi-sport participation (n = 126, 20%). Compared to non-participation, multi-sport participation during adolescence was associated with higher self-reported PA in early adulthood (β [95% confidence interval] = 0.26 [0.00-0.52], MET-minutes/week). No association was detected between sport trajectories and accelerometer-measured PA, body composition or blood pressure in early adulthood.

DISCUSSION

Our results partially support models suggesting the existence of distinct sport participation trajectories during adolescence and that multi-sport participation is associated with higher self-reported PA levels in adulthood. Our results do not support that sport participation trajectories during adolescence are linked to lower blood pressure or healthier body composition in adulthood.

Contemporaneous trajectories of physical activity and screen time in adolescents

Adolescents often report low moderate-to-vigorous physical activity (MVPA) and high screen time. We modeled sex-specific MVPA and screen time trajectories during adolescence and identified contemporaneous patterns of evolution. Data were drawn from 2 longitudinal investigations. The Nicotine Dependence in Teens (NDIT) study included 1294 adolescents recruited at age 12-13 years who completed questionnaires every 3 months for 5 years. The Monitoring Activities of Teenagers to Comprehend their Habits (MATCH) study included 937 participants recruited at age 9-12 years who completed questionnaires every 4 months for 7 years. MVPA was measured as the number of days per week of being active for at least 5 min (NDIT) or 60 min (MATCH). In both studies, screen time was measured as the number of hours spent weekly in screen activities. In each study, sex-specific group-based trajectories were modeled separately for MVPA and screen time from grade 7 to 11. Contemporaneous patterns of evolution were examined in mosaic plots. In both studies, 5 MVPA trajectories were identified in both sexes, and 4 and 5 screen time trajectories were identified in boys and girls, respectively. All combinations of MVPA and screen time trajectories were observed. However, the contemporaneous patterns of evolution were favourable in 14%-31% of participants (i.e., they were members of the stable high MVPA and the lower screen time trajectories). Novelty: MVPA and screen time trajectories during adolescence and their combinations showed wide variability in 2 Canadian studies. Up to 31% of participants showed favourable contemporaneous patterns of evolution in MVPA and screen time. Using uniform methods for trajectory modeling may increase the potential for replication across studies.

Intensity and frequency of physical activity and high blood pressure in adolescents: A longitudinal study

Despite limited evidence on the association between physical activity (PA) and blood pressure (BP) in youth, experts recommend that adolescents engage regularly in moderate-to-vigorous PA. We examined the relationships between PA intensity and frequency and the likelihood of having high BP in a population-based cohort of adolescents from Montréal, Canada. PA was self-reported every 3 months from grade 7 to 11, and BP was measured at ages 12.8, 15.2, and 17.0 years on average. We analyzed data from 993 participants (mean [SD] age = 16.0 [1.0], 51.6% female) with BP data at ages 15.2 and/or 17.0 years, using pooled ordinal logistic regression. BP (normal/elevated/hypertensive range) was the outcome, and past-year PA intensity and frequency were potential predictors. Eight percent of participants had elevated BP (120-129/<80), and 3.2% had BP in the hypertensive range (≥130/≥80). Participants engaged in a median (interquartile range) of 7.0 (4.5, 9.3) and 5.5 (2, 10.8) moderate and vigorous PA sessions/week, respectively. After adjusting for age, sex, mother's education, use of alcohol and cigarette consumption, engaging in PA more intense than light during the previous year was associated with a lower odds of having BP in the hypertensive range (ORs [95% CIs] = 0.93 [0.88, 0.97] to 0.97 [0.94, 0.99]). The relationships were not altered by adjusting for BMI. Our findings support recommendations that adolescents engage in at least moderate PA on a regular basis to prevent development of BP in the hypertensive range.

Behavioral, contextual and biological factors associated with obesity during adolescence: A systematic review

INTRODUCTION/OBJECTIVE

Adolescence is a critical period for the development of obesity. Obesity arises from a complex interaction between several factors, which are not yet fully understood. Therefore, the purpose of this review was to identify and assess the peer-reviewed scientific literature on the behavioral, contextual and biological factors associated with obesity in adolescents.

METHODS

PubMed and Scopus were systematically searched to identify prospective cohort studies concerning the relation between behavioral, contextual and biological factors and obesity in adolescents aged 10 to 18 years.

RESULTS

40 studies published between the year 2000 and 2018 were included. A positive consistent association between genetic factors and obesity during adolescence was found. Also, there is evidence to support the association between socioeconomic status and obesity. There was conflicting evidence for the contribution of dietary intake, physical activity, sedentary behavior, sleep, food store environment, school food environment. For the remaining factors no associations were found, or no conclusions could be drawn due to the limited number of studies identified.

CONCLUSIONS

Further prospective studies that assess multiple obesity determinants simultaneously and use state-of-art measures are warranted to aid in the development of effective strategies and interventions to prevent obesity during adolescence.

Relationships Between Current and Past Binge Drinking and Systolic Blood Pressure in Young Adults

PURPOSE

Heavy episodic (i.e., "binge") drinking (i.e., ≥five drinks/occasion) is highly prevalent among young adults; those who binge do so four times per month on average, consuming nine drinks on average on each occasion. Although it is well established that chronic heavy drinking (≥two alcoholic beverages per day) increases the risk of hypertension, the relationship between binge drinking and blood pressure is not well described. Our aim was to describe the relationship between frequency of binge drinking, both current (at age 24 years) and past (at age 20 years), and systolic blood pressure (SBP) at age 24 years.

METHODS

Participants (n = 756) from the longitudinal Nicotine Dependence in Teens study reported alcohol consumption at ages 20 and 24 years and had SBP measured at age 24 years. We examined the association between binge drinking and SBP using multiple linear regression, controlling for sex, race/ethnicity, education, monthly drinking in high school, cigarette smoking, and body mass index.

RESULTS

Compared to nonbinge drinkers, SBP at age 24 years was 2.61 [.41, 4.82] mm Hg higher among current monthly bingers and 4.03 [1.35, 6.70] mm Hg higher among current weekly bingers. SBP at age 24 years was 2.90 [.54, 5.25] mm Hg higher among monthly bingers at age 20 years and 3.64 [.93, 6.35] mm Hg higher among weekly bingers at age 20 years, compared to nonbinge drinkers.

CONCLUSIONS

Frequent binge drinking at ages 20 and 24 years is associated with higher SBP at age 24 years and may be implicated in the development of hypertension.

Cigarette smoking may modify the association between cannabis use and adiposity in males

INTRODUCTION

The few population-based studies that investigate the association between cannabis use and adiposity are inconclusive possibly because nicotine moderates the effect of cannabis on adiposity. The objective was to test the hypotheses that the association between cannabis use and adiposity in young men and women is modified by cigarette smoking.

METHODS

Data were drawn from the Nicotine Dependence in Teens (NDIT) study, a 13-year prospective cohort investigation of the natural course of nicotine dependence. A total of 271 males and 319 females aged 12-13years at cohort inception provided data on past-year cannabis use and number of cigarettes smoked per day in the past three months, at age 20years. Outcomes included change in body mass index (BMI) and in waist circumference (WC) from ages 17 to 24years. The hypothesis was tested in multiple linear regression models that included interaction terms for cannabis use and cigarette smoking and controlled for physical activity, sedentary behavior, alcohol use, and level of the outcome at baseline.

RESULTS

The association between cannabis use and change in adiposity was U-shaped in male non-smokers and in females, and an inverted U-shape in male smokers. In males, the interaction between cannabis use and cigarette smoking was significant in both the models for change in BMI (p=0.004; n=271) and change in WC (p=0.04; n=250). In females, the interaction between cannabis use and cigarette smoking was not significant.

CONCLUSION

Smoking cigarettes appears to modify the association between cannabis use and adiposity in young men.

Association of objectively measured physical activity with body components in European adolescents

Background

Physical activity (PA) is suggested to contribute to fat loss not only through increasing energy expenditure “per se” but also increasing muscle mass; therefore, it would be interesting to better understand the specific associations of PA with the different body’s components such as fat mass and muscle mass. The aim of the present study was to examine the association between objectively measured PA and indices of fat mass and muscle components independently of each other giving, at the same time, gender-specific information in a wide cohort of European adolescents.

Methods

A cross-sectional study in a school setting was conducted in 2200 (1016 males) adolescents (14.7 ±1.2 years). Weight, height, skinfold thickness, bioimpedance and PA (accelerometry) were measured. Indices of fat mass (body mass index, % fat mass, sum of skinfolds) and muscular component (assessed as fat-free mass) were calculated. Multiple regression analyses were performed adjusting for several confounders including fat-free mass and fat mass when possible.

Results

Vigorous PA was positively associated with height (p < 0.05) in males, whilst, vigorous PA, moderate-vigorous PA and average PA were negatively associated with all the indices of fat mass (all p < 0.01) in both genders, except for average PA in relation with body mass index in females. Regarding muscular components, vigorous PA showed positive associations with fat-free mass and muscle mass (all p < 0.05) in both genders. Average PA was positively associated with fat-free mass (both p < 0.05) in males and females.

Conclusion

The present study suggests that PA, especially vigorous PA, is negatively associated with indices of fat mass and positively associated with markers of muscle mass, after adjusting for several confounders (including indices of fat mass and muscle mass when possible). Future studies should focus not only on the classical relationship between PA and fat mass, but also on PA and muscular components, analyzing the independent role of both with the different PA intensities.