Are Infant Feeding Practices Associated with Early Childhood Overweight and Obesity? A Longitudinal Study of Participants of the Special Supplemental Nutrition Program for Women, Infants and Children

Obesity is a significant public health issue due to its prevalence and contribution to morbidity and mortality. Obesity prevention efforts in early life are important both because obesity has profound impacts on health status in childhood, and because obesity tracks from childhood to adulthood. The first thousand days in particular – from conception through age two years – may represent a critical period for obesity prevention because taste preferences and metabolic processes are shaped during this period. As such, infant feeding practices – including breastfeeding and complementary feeding practices – may be important predictors of obesity risk. However, there are significant gaps in our knowledge of the relationship between infant feeding practices and childhood obesity. The studies in this dissertation used longitudinal data from the WIC Infant and Toddler Feeding Practices Study-2 (WIC ITFPS-2) to understand the relationship between infant feeding practices - including breastfeeding duration and intensity, timing of introduction of complementary foods, and early introduction of sugar-sweetened foods and beverages - on weight trajectories and odds of overweight and obesity among low-income children up to age 3 years. Study 1 examined the relationship between breastfeeding duration and weight trajectories from age 6 months to 3 years and odds of overweight/obesity at ages 2-3 years. Mixed-effects regression models indicated that any breastfeeding (exclusive or partial) for at least 6 months and exclusive breastfeeding for at least 3 months were associated with healthier weight trajectories among both boys and girls. Breastfeeding was associated with significantly reduced odds of overweight/obesity for girls but not boys. Compared to girls who were never breastfed, those who were breastfed at all for less than 6 months had 45% lower odds of overweight/obesity while those breastfed at all for 6 months or longer had 65% lower odds of overweight/obesity. Compared to g