Predictors of fatness and physical fitness in nine-year-old Icelandic school children

Introduction. In recent years, the prevalence of overweight and obese children has increased in Iceland, as in most Westernized countries. The main objectives of this study were to assess predictors of fitness and fatness of 9-year-old school children in Iceland. Methods. In total, 488 subjects (73.3% participation rate) from 18 randomly selected primary schools participated in this cross-sectional study. Height, weight, sum of four skinfolds and other anthropometric measures were performed on all children. Fitness was assessed via a maximal cycle ergometer test in 229 children and of those, 177 wore Actigraph accelerometers to measure physical activity over five consecutive days. Questionnaires regarding family background and lifestyle were completed by 361 mothers and 332 fathers. Results. The main findings from our study showed fatness, area of living and sex, as well as background variables, such as fathers' smoking and income, and number of sport practices attended per week were important predictors of fitness (best-fit model: R-sq = 0.48, p < 0.0001). In addition, parental body mass index (BMI), mothers' smoking and physical activity and children's objective measure of physical activity were found to be important predictors of children's fatness (best-fit model: R-sq = 0.23, p < 0.0001). Conclusion. These results provide information about predictors of fitness and fatness of 9-year-old children and emphasize the inverse association between the two. Further, our results suggest that mothers have a stronger influence on children's weight than fathers but the opposite may be true for fitness.