This study examined the association between timing of introduction of solid foods during infancy and obesity at 3 years of age (defined as BMI for age and gender ≥95th percentile) in 847 children. The primary exposure was the timing of introduction of solid foods, categorized as less than 4 months after birth, 4 to 5 months, or ≥6 months after birth. Separate analysis was conducted for infants who were breastfed for at least 4 months (“breastfed”) and infants who were never breastfed or stopped breastfeeding before the age of four months (“formula-fed”). In the first 4 months of life, 568 infants (67%) were breastfed and 279 (32%) were formula-fed. At age 3 years, 75 children, an alarming 9%, were obese. Among breastfed infants, the timing of solid food introduction was not associated with odds of obesity (OR 1.1, 95%CI 0.3-4.4). However, among formula-fed infants, introduction of solid foods before 4 months of age was associated with a sixfold increase in odds of obesity at age 3 years, and this association was not explained by rapid early growth (OR after adjustment 6.3, 95%CI 2.3-6.9). Pediatrics. 2011 Feb 7. PMID: 21300681.
