How much does overweight impact the adolescent developmental process?

To analyse the associations between body mass index (BMI) and health-related behaviours among Portuguese adolescents based on the three waves of the Health Behaviour in School-aged Children (HBSC) survey conducted in Portugal.

Data were derived from the three waves (1998, 2002 and 2006) of the World Health Organization collaborative cross-national survey HBSC, including 17, 024 public school students (6th, 8th and 10th grades). Separate analyses of the variables under study were individually conducted for each of the three waves of the survey, and for the total sample according to BMI (normal-weight and overweight/obese) using Chi square. At a second step, a multivariate logistic regression model was tested using all the variables that were significantly associated with normal or excess BMI values at a bivariate level, in order to determine whether they would predict being overweight, when controlling for all the others in the model.

Overweight adolescents reported their health as fair or poor more often, reported a poorer perception of academic achievement, were more likely than their peers to describe themselves as 'unhappy', and reported irritability or bad temper more often. According to our findings, being overweight can be predicted by being a male, being younger, having low body satisfaction, having a perception of poor academic achievement, of poor personal health and of being unhappy. Being overweight was not significantly predicted by the year of data collection.

Overweight adolescents were consistently far more likely to exhibit difficulties with their physical and emotional health when compared with their non-overweight peers. Although the effects of overweight on psychosocial functioning remain incompletely defined, they may constitute important determinants of overweight persistency, as well as have a detrimental effect on the adolescent's developmental process.