Relationships of physical activity and sugar-sweetened drink consumption on fat mass growth of adolescents

Various factors, including low levels of physical activity (PA), and high consumption levels of sugar-sweetened drinks (SD), have been implicated in the general increase of fat mass (FM) levels seen in youth. Purpose: To determine if a significant relationship exists between fat mass (FM) and physical activity (PA) or sugar-sweetened drink (SD), in boys and girls, using longitudinal analysis. Methods: 105 boys and 103 girls were assessed repeatedly during childhood and adolescence, for a maximum of 7 years. Height was measured annually, as was fat free mass (FFM) and FM estimated by dual X-ray absorptiometry (DXA). PA was evaluated bi-annually using a questionnaire for children (PAQ-C/A: 1 low, 5 high), and SD was assessed using a 24-hour dietary intake questionnaire completed 1-4 times/year. Years from peak height velocity were used as a biological age indicator. Random effects models were used to analyze the data, subsequent to log linearization of the FM variable since it was not initially normally distributed. Results: The constructed model, controlling for maturation, FFM, and adjusted energy intake, found no interaction effect between SD and PA (p>0.05). After removal of the interaction term from the model, SD was found to have no significant relationship (p>0.05) with FM of boys or girls. In contrast, PA level was found to have a significant relationship (