Underweight, overweight, and obesity in childhood and adolescence are associated with adverse health consequences throughout the life-course. Our aim was to estimate worldwide trends in mean body-mass index (BMI) and a comprehensive set of BMI categories that cover underweight to obesity in children and adolescents, and to compare trends with those of adults. We pooled 2416 population-based studies with measurements of height and weight on 128·9 million participants aged 5 years and older, including 31·5 million aged 5-19 years. We used a Bayesian hierarchical model to estimate trends from 1975 to 2016 in 200 countries for mean BMI and for prevalence of BMI in the following categories for children and adolescents aged 5-19 years: more than 2 SD below the median of the WHO growth reference for children and adolescents (referred to as moderate and severe underweight hereafter), 2 SD to more than 1 SD below the median (mild underweight), 1 SD below the median to 1 SD above the median (healthy weight), more than 1 SD to 2 SD above the median (overweight but not obese), and more than 2 SD above the median (obesity). Regional change in age-standardised mean BMI in girls from 1975 to 2016 ranged from virtually no change (-0·01 kg/m2 per decade; 95% credible interval -0·42 to 0·39, posterior probability [PP] of the observed decrease being a true decrease=0·5098) in eastern Europe to an increase of 1·00 kg/m2 per decade (0·69-1·35, PP>0·9999) in central Latin America and an increase of 0·95 kg/m2 per decade (0·64-1·25, PP>0·9999) in Polynesia and Micronesia. The range for boys was from a non-significant increase of 0·09 kg/m2 per decade (-0·33 to 0·49, PP=0·6926) in eastern Europe to an increase of 0·77 kg/m2 per decade (0·50-1·06, PP>0·9999) in Polynesia and Micronesia. Trends in mean BMI have recently flattened in northwestern Europe and the high-income English-speaking and Asia-Pacific regions for both sexes, southwestern Europe for boys, and central and Andean Latin America for girls. By contrast, the rise in BMI has accelerated in east and south Asia for both sexes, and southeast Asia for boys. Global age-standardised prevalence of obesity increased from 0·7% (0·4-1·2) in 1975 to 5·6% (4·8-6·5) in 2016 in girls, and from 0·9% (0·5-1·3) in 1975 to 7·8% (6·7-9·1) in 2016 in boys; the prevalence of moderate and severe underweight decreased from 9·2% (6·0-12·9) in 1975 to 8·4% (6·8-10·1) in 2016 in girls and from 14·8% (10·4-19·5) in 1975 to 12·4% (10·3-14·5) in 2016 in boys. Prevalence of moderate and severe underweight was highest in India, at 22·7% (16·7-29·6) among girls and 30·7% (23·5-38·0) among boys. Prevalence of obesity was more than 30% in girls in Nauru, the Cook Islands, and Palau; and boys in the Cook Islands, Nauru, Palau, Niue, and American Samoa in 2016. Prevalence of obesity was about 20% or more in several countries in Polynesia and Micronesia, the Middle East and north Africa, the Caribbean, and the USA. In 2016, 75 (44-117) million girls and 117 (70-178) million boys worldwide were moderately or severely underweight. In the same year, 50 (24-89) million girls and 74 (39-125) million boys worldwide were obese. The rising trends in children's and adolescents' BMI have plateaued in many high-income countries, albeit at high levels, but have accelerated in parts of Asia, with trends no longer correlated with those of adults. Wellcome Trust, AstraZeneca Young Health Programme.

Background and Objectives: Recent studies have shown the existence of a positive relationship between physical exercise, symptomatic improvement, and reduction of damage caused by comorbidities associated with autistic spectrum disorder (ASD) in children, adolescents, and adults. The aim of this systematic review with meta-analysis (SRM) was to estimate the effects of physical exercise (PE) on the stereotyped behaviors of children with a diagnosis of ASD in intervention studies. Materials and Methods: The design followed the PRISMA guidelines and the TREND statement to assess the quality of information in each study. Nine non-randomized intervention trial studies with low, moderate, and vigorous physical exercise, with a duration varying from 8 to 48 weeks and a frequency of 3 times a week, were included in the SRM. The dependent variable episodes of stereotypical behaviors was analyzed in all studies and assessed as the number of episodes demonstrated by the child in pre- versus post-exercise intervention conditions. Results: The eight studies included a total 129 children (115 males and 14 females) with an average age of 8.93 ± 1.69 years. Children with ASD showed a reduction of 1.1 in the number of occurrences of stereotypical behaviors after intervention with physical exercise. Conclusion: Evidence was found to support physical exercise as an effective tool in reducing the number of episodes of stereotypical behaviors in children diagnosed with ASD.

This study investigated whether parental participation in organized and unorganized physical activity (PA) was associated with children’s participation in extracurricular sport. The sample comprised 834 parents and their children (aged 6–10 years), living in central Portugal. Questionnaires assessed parental PA (organized and unorganized) and extracurricular sport participation in children (number of sports and frequency of participation). Multinomial logistic regression was applied to assess associations between parental and child physical behaviors. Having both parents active was significantly associated with frequent participation in more sports both in girls and boys but a strong relation according to gender was found. The odds of boys practicing more than one sport and more times per week were higher if they had an active father. Girls with physically active mothers, particularly with mothers practicing organized PA in a regular way, were engaged in more sports and practiced sport more times per week. The type of PA practiced by the parents was not related to boys’ participation in sport. Future interventions should be family-based and focus on the promotion of higher levels of parental PA, including organized, in order to improve their children’s active behaviors.

Research considering physical activity (PA), physical inactivity and health outcomes among urban and rural youth has produced equivocal findings. This study examined PA, physical inactivity, sedentary behaviours and cardiorespiratory fitness (CRF) in adolescents from urban and rural communities in the Portuguese Midlands. The sample included 362 adolescents (165 males, 197 females) of 13–16 years of age. CRF was assessed by the PACER test. A GT1M accelerometer was used to record 5 consecutive days of PA and time spent sedentary. Analyses of covariance (chronological age as co-variate) were performed to test the effect of the area of residence on sedentary behaviour, PA and CRF. Urban youth of both sexes spent less time in sedentary activities than rural youth. Urban males were more active than rural peers at the weekend, whereas urban females were significantly less active than rural females on week days and across all days assessed. Rural youth of both sexes had higher levels of CRF than urban youth. Area of residence was related to aerobic fitness, PA and time spent in sedentary behaviours among Portuguese youth. Interventions seeking to enhance health and active lifestyles in Portuguese youth should consider the potential impact of socio-geographic factors.

Sex differences in physical activity (PA) through pubertal maturation and the growth spurt are often attributed to changing interests. The contribution of sex differences in biological maturation to the adolescent decline has received limited attention. This study examined the contribution of somatic maturation to sex differences in objective assessments of sedentary behavior and PA in Portuguese adolescents (N = 302, aged 13–16 years). Maturation was estimated from the percentage of predicted mature stature and physically active and inactive behaviors assessed with Actigraph GT1M accelerometers. The influence of age, sex and their interaction on body size, maturation and physical behaviors were examined using factorial ANOVA and, subsequently, ANCOVA (controlling for maturation) tested the effect of sex. Males spent more time in MVPA and less time in sedentary behavior than females. However, sex differences were attenuated when maturation was controlled; thus suggesting that maturity may play an important role in adolescent behaviors.

Background and Objectives: Childhood obesity and being overweight are influenced by the family environment, diet, sleep, and mental health, with parents playing a key role in shaping behaviors through routines and practices. Healthy parental habits can encourage positive outcomes, while poor routines and stress often lead to unhealthy weight gain. This study analyzed the impact of parental behaviors on children’s lifestyles and habits, as well as the trend and intensity of the effect of these behaviors on different age groups. Methods: A systematic review of 1504 articles from Web of Science, PubMed, Scopus, and APA PsycNet (as of 22 July 2024) included studies on parents and children aged 4–18 years, focusing on physical activity, sleep, screen time, nutrition, and mental health. Twenty-six studies were analyzed, including 19 cross-sectional and 7 longitudinal studies. The outcomes included physical activity, sedentary behaviors, eating and sleeping habits, mental health, and BMI. Bias was assessed using JBI tools according to the GRADE framework and Newcastle-Ottawa Quality Assessment. Results: The studies involved 89,545 youths and 13,856 parents. The key findings revealed associations between parental physical activity, sleep, dietary habits, mental health, screen time, and their children’s BMIs. Parenting styles significantly influence children’s behaviors. This review highlights the crucial influence of parenting styles and behaviors on children’s physical activity, diet, sleep, and mental health, emphasizing the link between family dynamics and childhood obesity. The findings stress the importance of targeting parental habits in interventions focused on healthy routines and stress management. Longitudinal studies are needed to determine causality, while research involving diverse populations is essential to enhance the applicability of these findings.