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.

Body-mass index (BMI) has increased steadily in most countries in parallel with a rise in the proportion of the population who live in cities^1,2. This has led to a widely reported view that urbanization is one of the most important drivers of the global rise in obesity^3–6. Here we use 2,009 population-based studies, with measurements of height and weight in more than 112 million adults, to report national, regional and global trends in mean BMI segregated by place of residence (a rural or urban area) from 1985 to 2017. We show that, contrary to the dominant paradigm, more than 55% of the global rise in mean BMI from 1985 to 2017—and more than 80% in some low- and middle-income regions—was due to increases in BMI in rural areas. This large contribution stems from the fact that, with the exception of women in sub-Saharan Africa, BMI is increasing at the same rate or faster in rural areas than in cities in low- and middle-income regions. These trends have in turn resulted in a closing—and in some countries reversal—of the gap in BMI between urban and rural areas in low- and middle-income countries, especially for women. In high-income and industrialized countries, we noted a persistently higher rural BMI, especially for women. There is an urgent need for an integrated approach to rural nutrition that enhances financial and physical access to healthy foods, to avoid replacing the rural undernutrition disadvantage in poor countries with a more general malnutrition disadvantage that entails excessive consumption of low-quality calories.

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.

Objectives: Obesity is a major public health concern worldwide. This study aims to investigate the accuracy of parental perception of child's weight and related factors as well as how underestimation is associated with the prevalence of childhood obesity.Methods: Data from 793 parents and respective children (6‐10 years) were collected during the spring of 2013 and 2014. Height and weight were measured and used to calculate body mass index and obesity was classified using the International Obesity Task Force. Parents' perception of child's weight and socio‐demographic characteristics were accessed by a questionnaire. Statistical tests were used, controlling for biological and social covariates.Results: About 33% of parents misperceived their child's weight, of which 93% underestimated it. Different factors were found associated with greater parental underestimation according to children's weight status (ie, younger age) and sex (ie, higher mother's BMI, lower parental education, and household income for girls; living in an urban place for boys). Underestimation among girls, compared to boys, was more associated with socio‐economic features of the family. For both sexes, children with excess weight were more likely to be underestimated by their parents. Parents who underestimated their child's weight were 10 to 20 times more likely to have an obese child.Conclusions: Findings suggest a social desirability bias in parental reports of child weight status. While some parents recognize their child's weight, others may feel embarrassed to discuss the fact that their child is overweight/obese and may feel reluctant in seeking the advice of a health care professional.

Background/Objectives: The literature on consumption of ultra-processed food (UPF) using the NOVA classification is still limited. Therefore, the aim of the present study was twofold: (i) to compare the UPF consumption, sedentary behaviors, and well-being perception between boys and girls; and (ii) to investigate the association between the UPF consumption and risk of overweight, sedentary behaviors, and well-being in adolescents. Methods: The present cross-sectional study comprised a sample of 245 adolescents (131 boys) aged 12–17 years-old (M = 14.20; SD = 1.09). Height and weight were assessed, and subsequently, the BMI was computed; furthermore, total body fat percentage was measured with bioelectrical impedance. Daily consumption of UPF was assessed by the NOVA screener and time spent sedentary was assessed by the Midlands Behavior Health 2024 questionnaire. The Mental Health Continuum-Short Form (MHC-SF) was used to measure adolescents’ psychosocial well-being. Pearson’s correlations and logistic regression analysis were used, controlling for biological, behavioral, and socio-economic confounders. Results: No sex differences were observed for the different UPF NOVA subscales. Boys reported higher computer use levels than girls on the weekend (p = 0.025), and they spent more time playing electronic games during the week (p = 0.005) and on the weekend than their female counterparts (p < 0.001). Moreover, boys reported higher scores in all well-being dimensions (p < 0.001) than girls. Conclusions: The findings revealed, after controlling for sex, sedentary time, and active behaviors, adolescents who consumed UPF on the previous day tended to be associated with a higher risk of being overweight, but also marginally without statistical significance (OR = 0.91, 95% CI: 0.83–1.01, p = 0.06). Of relevance, the present study revealed that both boys and girls of mothers with high educational levels were less likely to be classified as overweight or obese youth.

Background: Children are often exposed to too much screen time but few studies have explored the use of old and new digital media among young children. This study assesses screen time, including traditional and mobile devices, in pre-school and elementary school-aged children, according to their gender, age, and socioeconomic position (SEP). Methods: A total of 8430 children (3 to 10 years; 50.8% boys) from the north, center and south-central Portugal were included in the present study. Data was collected by a parental questionnaire during 2016/2017. Children’s screen time (by media device, weekdays and at the weekend; calculated by mean minutes per day) were reported by parents. Analysis were carried to compare screen time by children’s age, gender and family SEP (classified using father’s educational degree). Results: Daily screen time was high both in children aged 3 to 5 and 6 to 10 years – 154 min/day (95% CI: 149.51–158.91) and 200.79 min/day (95% CI: 197.08–204.50), respectively – and the majority of children, independently of their gender, exceed the recommended 2 h/day of screen viewing. Children are still primarily engaging in screen time through television but the use of mobile devices, particularly tablets, were already high among 3 year-old children and increased with age. SEP was a negative predictor of screen time in the linear regression analysis, including after adjustment. Conclusions: Considering the negative health impacts of excessive screen time, recognizing subgroups at risk of excessive screen time and identifying how each device is used according to age is fundamental to enable appropriate future interventions. The screen time in children aged 3–10 years is longer than the recommended, particularly among boys and in those children from lower SEP. Parents and policymakers should have in mind that children spend most of their screen time watching television but mobile devices are becoming extremely popular starting at a young age.