Abstract
The analysis was performed on a database including 17,427 records of subjects aged 7-18 years, randomly sampled from a population of Polish students. Thinness was determined using international cut-off points, defined to pass through body mass index of 18.5 kg/m(2) at the age of 18. The weighted prevalence of thinness and odds ratios with 95% confidence interval were estimated for gender, birth weight, level of schooling and school location, gross domestic product (GDP) per inhabitant, family income and maternal education. Body height was analysed according to body mass and birth weight categories. The prevalence of thinness was higher among children with low birth weight and among girls. The prevalence of thinness decreased with increasing GDP per inhabitant. In analysis by level of schooling: primary-middle-secondary, prevalence of thinness decreased among boys and increased among girls. Thin students were significantly shorter than other students, and thin girls less likely participated in physical education. CONCLUSION: Gender and socioeconomic factors are important determinants of thinness among Polish children and adolescents. Public health strategies should address family eating practices to prevent negative effects of weight deficit, especially among girls/children from low GDP regions. What is Known: • Socioeconomic factors and gender influence weight status of children and adolescents. What is New: • The first time the prevalence and determinants of thinness based on data from a nationally representative, weighted sample of Polish children aged 7-18 years were presented. • The analysis shows how gender and socioeconomics determinants influence the prevalence of thinness among children and adolescent in post-transformation country and can be used to international comparisons.