Abstract
BACKGROUND: Sugar-sweetened beverages (SSB) are considered a risk factor for obesity. OBJECTIVE: The objective of the current study was to investigate associations between the predictors of beverage and energy intakes and mean adequacy ratios (MARs), and the outcome of body mass index (BMI) z scores, in a birth cohort using longitudinal models. DESIGN: This was a longitudinal analysis of secondary data. PARTICIPANTS/SETTING: Participants in the Iowa Fluoride and Iowa Bone Development Studies with two beverage intake questionnaires completed between ages 2 and 4.7 years or 5 and 8.5 years or one questionnaire between ages 9 and 10.5, 11 and 12.5, 13 and 14.5, or 15 and 17 years (n=720); two food and beverage diaries completed between ages 2 and 4.7 years or 5 and 8.5 years or completion of the Block's Kids' Food Frequency Questionnaires at age 11, 13, 15, or 17 years (n=623); and anthropometric measures at the corresponding age 5-, 9-, 11-, 13-, 15-, or 17-year examination(s). PREDICTORS: Mean daily 100% juice, milk, SSB, water/sugar-free beverage, and energy intakes and MARs averaged over ages 2 to 4.7, 5 to 8.5, 9 to 10.5, 11 to 12.5, 13 to 14.5, or 15 to 17 years were predictors. OUTCOME: BMI z score was the outcome. STATISTICAL ANALYSES: Linear mixed models were fit for each beverage, energy, and MAR variable, with the beverage, energy, or MAR variable as the predictor and BMI z score as the outcome. Beverage models were adjusted for energy and MAR and baseline socioeconomic status. RESULTS: SSB intake adjusted for energy intake, MAR, and baseline socioeconomic status was associated with BMI z score; each additional 8 oz SSB consumed/day throughout childhood and adolescence increased the BMI z score an average 0.050 units (95% CI 0.022 to 0.079; P=0.001). Adjusted water/sugar-free beverage intake (0.026 units; 95% CI 0.006 to 0.046; P=0.013) was modestly associated with BMI z score, while 100% juice (-0.001 units; 95% CI -0.059 to 0.057; P=0.97) and milk (0.022 units; 95% CI -0.007 to 0.052; P=0.13) intakes were not associated with BMI z scores. CONCLUSIONS: Higher SSB intakes were associated with increased BMI z scores throughout childhood and adolescence in Iowa Fluoride Study participants. Public health initiatives targeting SSB consumption during childhood and adolescence remain relevant.