Role of dietary intake and physical activity in reducing weight social inequalities among adolescents: an application of G-formula to PRALIMAP-INÈS trial.

Interventions aiming to reduce social inequalities of weight status in adolescents usually focus on lifestyle behaviours, but their effectiveness is limited. This study analysed the effect of achieving levels of dietary intake (DI) and/or physical activity (PA) guidelines on reducing social inequalities in weight status among adolescents. We included adolescents from the PRomotion de l'ALIMentation et de l'Activité Physique - INÉgalité de Santé (PRALIMAP-INÈS) trial with weight status data available at baseline and 1-year follow-up (n=1130). PA and DI were measured using the International Physical Activity Questionnaire and a validated food frequency questionnaire, respectively. We estimated the likelihood of a 1-year reduction in body mass index z-score (BMIz) and population risk difference (PRD) under hypothetical DI and PA levels and socioeconomic status using the parametric G-formula. When advantaged and less advantaged adolescents maintained their baseline DI and PA, we found social inequalities in weight status, with a PRD of a 1-year reduction in BMIz of -1.6% (-3.0%; -0.5%). These inequalities were not observed when less advantaged adolescents increased their proportion of achieving DI guidelines by 30% (PRD=2.2% [-0.5%; 5.0%]) unlike the same increase in PA (PRD= -3.9% [-6.8%; -1.3%]). Finally, social inequalities of weight status were not observed when levels of achievement of both PA and DI guidelines increased by 30% (PRD= 2.2% [-0.5%; 4.0%]). Enhancing DI rather than PA could be effective in reducing social inequalities in weight status among adolescents. Future interventions aiming to reduce these inequalities should mostly target DI to be effective.

Effectiveness of interventions to reduce social inequalities of weight status in adolescents: A systematic review and meta-analysis.

Many interventions are implemented in the public health context to overcome social inequalities of weight status in adolescents, but their effectiveness is challenged. This study aimed to examine the effectiveness of these interventions with a systematic review and meta-analysis. We systematically searched for reports of randomized control trials and quasi-experimental studies aiming to reduce social inequalities of weight status in adolescents in five electronic databases. The primary outcomes were social inequalities in weight-related outcomes (body mass index [BMI], BMI z score, waist circumference, percent body fat, prevalence of overweight/obesity). Interventions were effective when they reduced social inequalities in at least one weight-related outcome. Meta-analyses involved using random-effects models. The review included 38 publications (33 studies) with interventions mostly targeting disadvantaged adolescents (n = 29 studies), showing effectiveness in half of the studies (n = 19/33, 57.6%). The meta-analysis (27 studies) revealed that targeted interventions significantly reduced BMI z score (ß = -0.04 [95% CI -0.08, -0.01]), BMI (ß = -0.32 [-0.47, -0.18]), and waist circumference (ß = -0.84 [-1.48, -0.21]) but not percent body fat (ß = -0.27 [-0.71, 0.17]) or prevalence of overweight/obesity (odds ratio = 1.06 [0.85, 1.31]). This review shows moderate effectiveness of interventions targeting disadvantaged adolescents to reduce social inequalities of weight status. High-quality research with better implementation to reach their full potential is required to strengthen their effectiveness.

Longitudinal patterns of lifestyle behaviours in adolescence: a latent transition analysis.

The interdependence among eating behaviour (EB), physical activity (PA) and sedentary time (ST) suggests simultaneously identifying homogeneous profiles and describing their changes. This study aimed to (1) identify cross-sectional lifestyle behaviour profiles and their 2-year changes among French school-age adolescents and (2) identify factors associated with these profiles and changes. Longitudinal data from adolescents who participated in the PRomotion de l'ALIMentation et de l'Activité Physique trial were used. PA and ST were assessed with the International Physical Activity Questionnaire and EB with a FFQ. Profiles at baseline and their changes were identified by latent transition analysis. Multinomial logistic regression models were used to identify factors associated with profiles and their changes. Among 2390 adolescents included (14-18 years), five baseline profiles that differed mainly in EB were identified: 'healthy diet and high PA (7·9 %)', 'big eater and moderate to high PA (23·8 %)', 'healthy diet and low PA (31·2 %)', 'restrictive diet and moderate PA (20·6 %)' and 'sugar products, nibbling and moderate PA (16·5 %)'. Young adolescents, those who were overweight or obese and socially advantaged, were more in the 'healthy diet and low PA' than others. Boys, older and socially less advantaged adolescents exhibited more 'unfavourable' than 'mixed' changes, while adolescents with overweight or obesity had less 'unfavourable' than 'mixed' changes. In conclusion, adolescents were twice the number in the least than the most favourable profile. Findings highlighted the importance of EB among adolescents and suggest taking adolescents' sociodemographic and weight characteristics into account in interventions aimed at acting on adolescents' behaviours.