Objectives: Evidence supporting an association between sugar-sweetened beverage (SSB) intakes and obesity during childhood and adolescence is inconclusive due in part to the cross-sectional nature of most previous studies. Our objective was to assess longitudinal associations between beverage intakes and body mass indices throughout childhood and adolescence.
Methods: Mean daily beverage (oz) intakes of Iowa Fluoride Study participants (n=349 male, n=359 female) were calculated for ages 2-4.7, 5-8.5, 9-10.5, 11-12.5, 13-14.5 and 15-17 years from questionnaire-reported intakes of milk, 100% juice, sugar-sweetened beverages and water-based sugar-free beverages (WBB). Body mass indices (BMI) were calculated from weight and height measured at the corresponding age 5, 9, 11, 13, 15 and 17 year clinic exams. Linear mixed models were used to examine associations between the independent variables of age, sex, and beverage intakes, and the dependent variable of BMI z-scores.
Results: SSB intakes were significantly associated with BMI z-scores (Effect size 0.067; 95% Confidence Interval 0.031, 0.104; p<0.001). Specifically, for each additional 10oz SSB daily intake, on average, the BMI percentile for a subject at the 50th percentile would increase to the 52.7 percentile. Milk (Effect size 0.013; 95% Confidence Interval -0.024, 0.049; p=0.496), 100% juice (Effect size -0.030; 95% Confidence Interval -0.098, 0.039; p=0.394) and WBB (Effect size 0.025; 95% Confidence Interval -0.002, 0.051; p=0.065) intakes were not significantly associated with BMI z-scores. Females had slightly lower BMI z-scores than males for all beverage intakes; however, these mean differences were not statistically significant.
Conclusion: SSB intakes contributed to higher mean BMI z-scores throughout childhood and adolescence among Iowa Fluoride Study participants, suggesting that SSBs are an important, modifiable risk factor for obesity.