Contrary to findings of previous studies, a new report found that young children who were cared for by someone other than a parent were not at increased risk of obesity.
Most of the observational studies looking at whether attending child care is associated with weight status have found an increased risk of obesity among children in non-parental child care compared to those cared for by a parent.
“However, a major challenge is the fact that children in non-parental childcare and those in parental care may differ across many unmeasured variables not accounted for in existing studies,” the authors wrote in the study “Childcare Attendance and Obesity Risk” (Isong IA, et al. Pediatrics. Oct. 10, 2016, http://dx.doi.org/10.1542/peds.2016-1539).
Since a randomized, controlled study would be expensive and difficult to conduct, researchers used quasi-experimental techniques instead. These analyses minimized selection bias and unmeasured confounding factors.
Researchers used data from a nationally representative sample of about 7,200 children in the Early Childhood Longitudinal Study Birth Cohort to evaluate longitudinal associations between child care attendance at 2 years of age and body mass index (BMI) z-scores at the start of kindergarten.
The first analysis used standard techniques, controlling for variables such as race/ethnicity, socio-economic status and neighborhood safety. It showed children in non-parental child care at 24 months had higher BMI z-scores when they started kindergarten than youngsters who were cared for by a parent.
Researchers then analyzed the data using two quasi-experimental approaches that adjusted for observed and unobserved confounders. These results showed no significant association between type of child care and obesity.
Conventional analysis, the authors said, may not completely control for differences among children in various child care settings.
“For example, parents who choose to take care of their children at home may also be more likely to cook healthier diets or emphasize healthy habits than parents that send their children to child care,” the authors wrote. “This would imply that it is not childcare
per se which increases the risk of obesity but other unmeasured behaviors that tend to cluster among parents who stay home with their children, and which are correlated with child weight.”
They noted that quasi-experimental techniques have limitations, and the study followed children only until kindergarten.
Despite the limitations, they concluded that “our results do provide a richer picture that casts doubt on the hypothesis that non-parental childcare is associated with higher risk of obesity.”
In a related commentary titled “In the Absence of Clear Causation, Casting a Wider Net for Prevention” (Perrin EM, et al. Pediatrics. Oct. 10, 2016, http://dx.doi.org/10.1542/peds.2016-2895), the authors praised the study design. “This article is interesting, has face validity, and certainly will help assuage working parents’ guilt: placing children in childcare may not, in fact, put their children at risk for obesity.”
However, they expressed concern that child care centers that offer healthy food and time for physical activity may be more expensive than centers with less healthy practices, putting poor children at further risk for obesity.
They also discussed the role of pediatricians and suggested they help parents navigate child care options. Pediatricians also should advocate for improved quality standards that promote healthy eating and physical activity for children in child care centers.