Early Introduction of Solid Foods Linked to Risk for Early Childhood Obesity

From Medscape Medical News
Laurie Barclay, MD

February 7, 2011 — Early introduction of solid foods is linked to a risk for early childhood obesity, according to the results of a prospective prebirth cohort study reported online February 7 in Pediatrics.

"Parental feeding practices during early infancy, such as the timing of solid food introduction, may be 1 key modifiable determinant of childhood obesity," write Susanna Y. Huh, MD, MPH, from the Division of Gastroenterology and Nutrition, Children's Hospital Boston in Boston, Massachusetts, and colleagues.
"Data suggest that the introduction of solid foods earlier than 4 months of age is associated with increased body fat or weight in childhood or with greater weight gain during infancy, which itself predicts later adiposity. Other studies have found no association between the timing of solid food introduction and body fat or an association between delayed introduction of solid foods after 6 months and greater adiposity."

The goal of the study was to evaluate the association between timing of introduction of solid foods during infancy and obesity at age 3 years, defined as a body mass index for age and sex at the 95th percentile or above, using a cohort of 847 children enrolled in Project Viva. Timing of introduction of solid foods was categorized as younger than 4 months, ages 4 to 5 months, and 6 months or older. Logistic regression models were applied separately for infants who were breast-fed for at least 4 months ("breast-fed"; n = 568; 67%) and for infants who were never breast-fed or in whom breast-feeding was stopped before age 4 months ("formula-fed"; n = 279; 32%). These models were adjusted for child and maternal factors, including change in weight-for-age z score from 0 to 4 months as a marker of early infant growth.

Obesity was present in 75 children (9%) at age 3 years.
The timing of solid food introduction was not associated with odds of obesity in breast-fed infants, (odds ratio, 1.1; 95% confidence interval [CI], 0.3 - 4.4). However, introducing formula-fed infants to solid foods before age 4 months was associated with a 6-fold increase in odds of obesity at age 3 years, which was not explained by rapid early growth (odds ratio after adjustment, 6.3; 95% CI, 2.3 - 6.9).

"Among infants who were never breastfed or those who stopped breastfeeding before the age of 4 months, the introduction of solids before the age of 4 months was associated with a sixfold increase in the odds of obesity at the age of 3 years," the study authors write.

Limitations of this study include possible residual confounding; some loss of the cohort to follow-up; limited generalizability to more socioeconomically disadvantaged populations; and small numbers in some cells, leading to possible chance results.

"Among infants breastfed for 4 months or longer, the timing of the introduction of solid foods was not associated with the odds of obesity," the study authors conclude. "Increased adherence to guidelines regarding the timing of solid food introduction may reduce the risk of obesity in childhood."

The National Institutes of Health supported this study. The study authors have disclosed no relevant financial relationships.

Pediatrics. Published online February 7, 2011. Abstract