Overweight/obesity and factors associated with body mass index during adolescence: the VYRONAS study

Association between screen time and dietary patterns and overweight/obesity among adolescents

ABSTRACT Objective The association between screen time and dietary patterns and overweight/obesity among adolescents was analysed in this study. Methods In this cross-sectional study, 963 Brazilian adolescents, aged between 11 and 14 years were evaluated. Body mass index was used to assess overweight/obesity. Dietary patterns and screen time were assessed using qualitative questionnaires. Principal component analysis was used to obtain dietary patterns. Confounder variables were: type of school (public or private), sexual maturation, mother’s weight and mother’s education. The Chi-square test was used for the crude analysis; for the adjusted analysis was used Poisson regression with sample weighting. Results Overweight/obesity prevalence was 29.8% and statistically higher among boys (34.7%). Higher screen time prevalence was 39.1%. The dietary patterns obtained were: obesogenic; coffee and dairy products; traditional Brazilian meal; fruit and vegetables; bread and chocolate milk. The dietary pattern that more closely represented student food consumption was the obesogenic pattern. Screen time was not significantly associated with overweight/obesity. The obesogenic pattern (in both sexes), the coffee and dairy products pattern, and the bread and chocolate milk pattern (only in girls), were inversely associated with overweight/obesity. In this study, dietary patterns influenced overweight/obesity, although in some cases, in an inverse way from what expected. Conclusion A high prevalence of overweight/obesity and a high proportion of screen time activities among the adolescents were observed. Our results indicate a high consumption of unhealthy dietary pattern among adolescents.

Associations between obesity, adverse behavioral patterns and cardiovascular risk factors among adolescent inhabitants of a Greek island

BACKGROUND

Excess weight, unhealthy lifestyle habits and their sequelae have become a well-recognized public health problem in most countries. The objective of the study was to examine the relationship of adolescent overweight/obesity with behavioral habits and their association with blood pressure (BP) and lipid profile.

METHODS

Anthropometric parameters, lifestyle, BP and lipid profile of 736 adolescents were evaluated cross-sectionally. The classifications of normal weight, overweight and obese were based on BMI z-scores.

RESULTS

About 42.1% of adolescents were overweight/obese, 11.3% were smokers, 33.2% consumed alcohol and 34% reported low activity. Males began smoking earlier, consumed alcohol more often, exercised less and spent more screen time than females. Alcohol consumption was more prevalent among smokers and was associated with higher BP and dyslipidemia. Smokers exercised less intensely and had lower high density lipoprotein-cholesterol (HDL-C) than non-smokers. Obesity was a risk factor for higher BP and dyslipidemia. Longer screen time was associated with higher triglycerides, while intense physical activity with lower systolic BP.

CONCLUSIONS

Obesity is related to an adverse lipid and BP profile during adolescence. Clustering of hazardous habits was observed, which is known to aggravate the cardiovascular risk.

Identifying target groups for the prevention of depression in early adolescence: the TRAILS study

BACKGROUND

Depression in adolescence is associated with long-term adverse consequences. The aim of the present study is to identify target groups at increased risk of developing depression in early adolescence, such that prevention is associated with the largest health benefit at population-level for the least effort.

METHODS

The analyses were conducted on data of the first (age range 10-12) and fourth (age range 17-20) wave of a population-based cohort study (N=1538). The Composite International Diagnostic Interview (CIDI) was used to assess onset of major depression in early adolescence. High-risk groups were identified using exposure rate, incidence rate and population attributable fraction.

RESULTS

Prevention of depression onset in early adolescence is best targeted at children with one of the following risk profiles: a high body mass index in combination with (1) maternal depression (2) female gender, and (3) parental emotional rejection.

LIMITATIONS

Age of onset of depression was assessed retrospectively.

CONCLUSIONS

Only a few risk indicators are needed to identify a relatively small group which accounts for a substantial percentage of the new cases of depression in early adolescence.

Systematic review of sedentary behaviour and health indicators in school-aged children and youth

Accumulating evidence suggests that, independent of physical activity levels, sedentary behaviours are associated with increased risk of cardio-metabolic disease, all-cause mortality, and a variety of physiological and psychological problems. Therefore, the purpose of this systematic review is to determine the relationship between sedentary behaviour and health indicators in school-aged children and youth aged 5-17 years. Online databases (MEDLINE, EMBASE and PsycINFO), personal libraries and government documents were searched for relevant studies examining time spent engaging in sedentary behaviours and six specific health indicators (body composition, fitness, metabolic syndrome and cardiovascular disease, self-esteem, pro-social behaviour and academic achievement). 232 studies including 983,840 participants met inclusion criteria and were included in the review. Television (TV) watching was the most common measure of sedentary behaviour and body composition was the most common outcome measure. Qualitative analysis of all studies revealed a dose-response relation between increased sedentary behaviour and unfavourable health outcomes. Watching TV for more than 2 hours per day was associated with unfavourable body composition, decreased fitness, lowered scores for self-esteem and pro-social behaviour and decreased academic achievement. Meta-analysis was completed for randomized controlled studies that aimed to reduce sedentary time and reported change in body mass index (BMI) as their primary outcome. In this regard, a meta-analysis revealed an overall significant effect of -0.81 (95% CI of -1.44 to -0.17, p = 0.01) indicating an overall decrease in mean BMI associated with the interventions. There is a large body of evidence from all study designs which suggests that decreasing any type of sedentary time is associated with lower health risk in youth aged 5-17 years. In particular, the evidence suggests that daily TV viewing in excess of 2 hours is associated with reduced physical and psychosocial health, and that lowering sedentary time leads to reductions in BMI.

Socio-demographic and lifestyle factors associated with overweight in a representative sample of 11-15 year olds in France: results from the WHO-Collaborative Health Behaviour in School-aged Children (HBSC) cross-sectional study

Background

The prevalence of overweight in children and adolescents is high and overweight is associated with poor health outcomes over short- and long-term. Lifestyle factors can interact to influence overweight. Comprehensive studies linking overweight concomitantly with several demographic and potentially-modifiable lifestyle factors and health-risk behaviours are limited in adolescents - an age-group characterized by changes in lifestyle behaviours and high prevalence of overweight. Thus, the objective of the current study was to examine the association of overweight with several socio-demographic and lifestyle variables simultaneously in a representative sample of adolescents.

Methods

A nationally representative sample of 11-15 year-olds (n = 7154) in France participated as part of the WHO-Collaborative Health Behaviour in School-aged Children (HBSC) study. Students reported data on their age, height, weight, socio-demographic variables, lifestyle factors including nutrition practices, physical activity at two levels of intensity (moderate and vigorous), sedentary behaviours, as well as smoking and alcohol consumption patterns using standardized HBSC protocols. Overweight (including obesity) was defined using the IOTF reference. The multivariate association of overweight with several socio-demographic and lifestyle factors was examined with logistic regression models.

Results

The adjusted odds ratios for the association with overweight were: 1.80 (95% CI: 1.37-2.36) for low family affluence; 0.73 (0.60-0.88) for eating breakfast daily; 0.69 (0.56-0.84) for moderate to vigorous physical activity (MVPA); and 0.71 (0.59-0.86) for vigorous physical activity (VPA). Significant interactions between age and gender as well as television (TV) viewing and gender were noted: for boys, overweight was not associated with age or TV viewing; in contrast, for girls overweight correlated negatively with age and positively with TV viewing. Fruit and vegetable intake, computer and video-games use, smoking and alcohol consumption were not associated with overweight.

Conclusions

In multivariate model, family affluence, breakfast consumption and moderate to vigorous as well as vigorous physical activity were negatively associated with overweight. These findings extend previous research to a setting where multiple risk and protective factors were simultaneously examined and highlight the importance of multi-faceted approaches promoting physical activity and healthy food choices such as breakfast consumption for overweight prevention in adolescents.

[Overweight and obesity in childhood and adolescence]

Firstly, essential developmental aspects of the focused periods of life, namely childhood and adolescence, are discussed. Furthermore, different issues of overweight and obesity in childhood and adolescence are highlighted. Besides the definition and the assessment, possibilities of classification and epidemiological aspects are of interest. Physical and psychiatric consequences, which can be associated with obesity are also presented. In the context of a model of multifactorial genesis of obesity, different causing and maintaining factors are described. In addition to genetic and biological risk factors, the significance of several psychosocial factors is illustrated. Finally, the focus is on the therapy of obesity in childhood and adolescence.

Links Between Adolescent Physical Activity, Body Mass Index, and Adolescent and Parent Characteristics

Identification of the relationships between adolescent overweight and obesity and physical activity and a range of intrapersonal and interpersonal factors is necessary to develop relevant interventions which target the health needs of adolescents. This study examined adolescent body mass index (BMI) and participation in moderate and vigorous physical activity (MVPA) and their associations with school year, adolescent nutrition and sedentary behaviors, parent BMI, parent physical activity, and parent support adolescent physical activity. Participants included 295 adolescents and their parents. Logistic regression was used to examine associations between adolescent BMI, MVPA, and the range of adolescent and parent characteristics. Results indicated that parents and home environments play significant roles in the development and maintenance of adolescent overweight/obesity of physical activity behaviors. School-based interventions should ensure high levels of parent involvement and target male adolescents to reduce time spent in small screen recreation and female adolescents to increase participation in MVPA.

Relation of age-related cataract with obesity and obesity genes in an Asian population

Obesity shows an inconsistent association with cataract. Causality has not been established. Polymorphisms at the fat mass- and obesity-associated (FTO) locus are associated with obesity and offer an opportunity to examine the obesity-cataract association using a mendelian randomization approach. The authors conducted a population-based study among Singaporean Malay adults (2004-2006) in which nuclear, cortical, and posterior subcapsular (PSC) cataracts were assessed and defined by slit-lamp examination using Lens Opacity Classification System III. Obesity was defined as body mass index (weight (kg)/height (m)(2)) > or =30. The study included 3,000 subjects, of whom 1,339 (44.6%) had cataract (848 (28.3%) nuclear, 939 (31.3%) cortical, and 285 (9.5%) PSC). After multivariable adjustment for age, gender, diabetes, hypertension, smoking, and education, obesity was significantly associated with cortical (odds ratio (OR) = 1.31, 95% confidence interval (CI): 1.01, 1.71) and PSC (OR = 1.60, 95% CI: 1.10, 2.32) cataracts but not nuclear cataract. FTO single nucleotide polymorphisms known to be associated with obesity in this study population were not associated with cortical or PSC cataract but were associated with nuclear cataract (OR = 1.33, 95% CI: 1.11, 1.58), even in multivariate analyses controlling additionally for body mass index, diabetes, hypertension, and smoking (OR = 1.30, 95% CI: 1.08, 1.55). These results do not support a causal association between obesity and cortical or PSC cataract. The FTO gene may be involved in the pathogenesis of nuclear cataract.