Sociodemographic factors and risk-taking behaviour during adolescence and obesity among more than 40 000 Danes.

Objective: The prevalence of obesity has increased in the last decades in the Western world. The aim of the present study was to examine the association between risk-taking behaviour in adolescence and adult obesity in men and women. Furthermore, we wished to describe social differences in obesity in Denmark.

Design: Two population-based questionnaire studies (2004-2005 and 2006-2007) were used to collect information on weight and height, sociodemographic factors and factors regarding risk-taking behaviour during adolescence. Data were analysed using multivariate logistic regression.

Setting: Denmark.

Subjects: Individuals aged 18-45 years (men: n 22 827, participation rate 71·0%; women: n 20 870, participation rate 81·4%).

Results: The prevalence of overweight and obesity was respectively 37·8% and 10·6% in men and 20·1% and 9·7% in women. In both sexes, obesity was found to be associated with older age, low level of schooling and living outside the capital centre. In relation to risk-taking behaviour, young age (≤13 years) at first intercourse significantly increased the odds of being obese in adulthood (men: OR = 1·34, 95% CI 1·04, 1·71; women: OR = 1·66, 95% CI 1·27, 1·99). In women specifically, young age at start drinking alcohol (≤12 years) was associated with obesity.

Conclusions: Sociodemographic factors, in particular age, level of schooling and area of residence, are associated with obesity in both men and women. Risk-taking behaviour during adolescence seems to cluster in both obese men and obese women, however most convincingly in women.