A lot of attention has been focused on obesity, however, the other extreme-thinness-may lead to inhibition of physical and intellectual development. The aim was to assess the prevalence of thinness and determine the associated factors in children from rural populations. We used data from the cross-sectional sample of 3048 children, examined in schools from a district in southern Poland. The sample included 89% of the district departments, and included a proportion of rural and small town populations-a representative one for the region. Thinness was determined based on the criteria proposed by Cole and Lobstein. Biological, sociodemographic and lifestyle factors were analysed. The odds ratio (OR) and 95% confidence interval (CI) were calculated using logistic regression analysis. The prevalence of thinness was 11.5% in boys and 13.5% in girls. In the younger group, it was similar in boys and girls at 11.8%; whereas in the older group, it was 11.1% and 14.5%, respectively. The prevalence of thinness Grade 3 in girls was two times higher than in boys. The increased index of leisure time physical activity was connected with thinness in prepubertal boys. The mechanism determining the development of thinness is very complex and further exploration of this trend is recommended.
Keywords: BMI; physical activity; risk factors.