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-W. Bradford Wilcox
Associate Professor of Sociology, University of Virginia
Epidemiologists have known for some time that children in day-care centers are distinctively vulnerable to a number of health risks. Besides the respiratory and other diseases that often spread in the day-care center, obesity is now a problem—with long-term consequences—showing up among a troubling number of day-care children and attracting the attention of public-health officials. Now a new study out of Denmark concludes that this problem may develop very early, even among day-care infants.
Conducted by an international team of researchers affiliated with Harvard, Duke, and the University of Copenhagen, this new study should attract attention at a time when health officials worldwide regard obesity—especially child and adolescent obesity—as an urgent concern. As the authors of this new study acknowledge, “Obesity rates have increased globally over the past decade,” with particularly alarming rates evident in affluent nations. Stressing that this problem is manifest “even in young children,” the researchers note that “in preschool-aged children, the worldwide prevalence of obesity increased from approximately 4% in 1990 to 7% in 2010.” Explaining why health officials worry so much about child obesity, the researchers stress that “obesity and excessive weight gain in early childhood have been linked to later obesity and chronic health conditions such as diabetes mellitus and cardiovascular disease in adulthood.” “Even in infancy,” they add, “excessive weight gain . . . has been associated with obesity in later life.”
Having identified just what is at stake in their inquiry, the authors of the new study set to work examining the relationship between infant weight gain and time spent in day-care centers in Denmark, a nation much lauded by progressives for both its generous maternal-leave policies and its well-funded childcare system. They scrutinize data collected between 1997 and 2002 for 27,821 infants during their first year of life. The pattern that emerges in these data is quite clear, though not dramatic: “Child care in the first year of life,” the researchers conclude, “was associated with slightly higher weight at 12 months.”
More specifically, the data revealed that every 30 days that a child spent in out-of-home child care predicted “a modestly higher BMI [Body Mass Index] z-score at 12 months,” even after statistically accounting for differences in child circumstances due to maternal smoking, maternal pregnancy weight, breastfeeding, and household income. Not surprisingly, then, “child care use was [also] associated with increased odds of being overweight/obese at 12 months of age.”
The researchers concede that they have documented only a “modest” association between out-of-home child care and infant weight gain. Nevertheless, they worry: “Over time, the cumulative effect of additional time in child care may have a substantial impact on weight status.”
The obesity risk associated with out-of-home child care most definitely does not reflect an economic disadvantage—since the researchers find that children in such care actually came from “families with higher household incomes . . . [than] children cared for at home by a parent.” It certainly did not help children in day care that they were less often breastfed for 22 weeks or more compared to infants cared for at home. But the statistical analysis accounted for this significant difference—predictably, the linkage between out-of-home child care and infant weight gain was even more pronounced in the simpler statistical model that did not account for differences in breastfeeding.
As they reflect on their findings, the researchers emphasize that “early childhood may provide a window of opportunity for the prevention of obesity and the first year represents an especially critical period.” Consequently, they call for “intervention efforts to improve the child-care setting,” so creating “healthier environments where infants spend time . . . [and thus] help[ing] prevent the development of obesity in very young children.”
Though intervention has become a god term among scholars when referring to actions by government officials and professionals, a common-sense reading of this new study would suggest that the intervention most likely to protect infants from obesity is the one that puts children back in the care of their own mothers in their own homes.
(Sara E. Benjamin Neelon et al., “Early Child Care and Obesity at 12 Months of Age in the Danish National Birth Cohort,” International Journal of Obesity 39.1 : 33-38, emphasis added.)