600 - Associations between Infancy BMI, Appetite, and Body Composition

Poster Number: 600
Publication Number: 600.2981

Background: BMI in infancy is a strong predictor of obesity, yet relationships between infant appetite, BMI, and body composition are unclear.

Objective: To explore associations between infant appetite, weight, BMI, and body composition. We hypothesized that higher peak infancy BMI would be associated with higher fat mass and that higher general appetite (GA), food responsiveness (FR), and enjoyment of food (EF) and lower satiety responsiveness (SR) and slowness in eating (SE) would predict higher fat mass, BMI, and weight.

Design/Methods: We followed 80 term infants (55% female; parents 48% Hispanic, 32% Black, 23% White, 33% Spanish speaking), from 1-2 month well visits through 15 months. Parents reported infant appetite with the Baby Eating Behavior Questionnaire (BEBQ) at enrollment and again at 6 months. 1 in 4 infants were randomized to body composition analysis via air-displacement plethysmography at 4-6 months of age. Weight and BMI were extracted from the electronic health record and reviewed by multiple pediatricians for accuracy. We used linear regression to examine associations between GA, FR, EF, SR, and SE and 1-12 month changes in WHO weight-for-age (WFAZ) and BMI-for-age (BMIZ) Z-scores. We used pairwise correlation and linear regression to examine associations between attained peak BMI, BMIZ, WFAZ and body composition.

Results: 91% of infants were followed for the entire study period. 20 infants were randomized to obtain body composition and did not differ by birth weight (overall mean 3.39 kg), gestational age (mean 39 weeks), weight or BMI at 1 month or 1 year. Adjusting for birthweight and feeding type, each 1 kg/m2 increase in peak infancy BMI was associated with 2% higher fat mass (95% CI: 0.48-3.96, p=0.02). Each 1 unit higher 1 year WFAZ was associated with 400g and 5% higher fat mass (95% CI: 84-708g, p=0.02 and 95% CI: 0.9-8.3%, p=0.02), respectively, but was not associated with higher fat free mass. Appetite was correlated across time and we found no associations between appetite and WFAZ or BMIZ. However, 1 point increase in mean SE was associated with 421g lower fat mass (95% CI: 780-63, p=0.03) but not fat free mass, and 1 point increase in SR was associated with 482g higher fat free mass (95% CI: 12-950, p=0.05) but not fat mass.

Conclusion(s): Appetite measures of SE and SR predicted differences in fat mass and fat free mass, and several routine clinical growth measures, including peak infancy BMI, may be appropriate proxies for body composition and could inform risk stratification of adiposity-related comorbidities.