July 30 (HealthDay News) -- When infants attend day care in someone else's home, they're more likely to be heavier than average by the time they're toddlers, new research suggests.
Harvard researchers report in the August issue of Pediatrics that babies aged 6 months and younger who were cared for in someone else's home, rather than in their own home or at a day-care center, were more likely to weigh more in relation to their height at the ages of 1 and 3.
"An infant who was in child care in someone else's home in the first six months of life was 5 or so percentage points higher [on growth charts] at 1 or 3 years old than an infant who started at the same point but was cared for at home by another provider or at a center," said study author Sara Benjamin, a postdoctoral research fellow in the department of population medicine at Harvard Medical School in Boston.
Benjamin said it's not clear why this type of care may lead to heavier children. She said it could be a characteristic of the families that choose this type of care, or it could have something to do with this less formal day-care setting.
Between 9 percent and 12 percent of U.S. children under the age of 2 are overweight, according to background information in the study. Rapid weight gain during the first two years of life has been linked to becoming overweight later in childhood. Rapid weight gain in infancy has even been associated with higher blood pressure and wheezing in childhood and in adulthood.
In a random sample of 1,138 women, who began participating in the study while they were pregnant, 649 (57 percent) placed their infants in some sort of day care before they were 6 months old. Half of the babies included in the study were female, and two-thirds were white. About 15 percent were black and around 5 percent were Hispanic. For most families, the average household income was more than $70,000 annually.
For babies who went to day-care centers, the average number of hours spent in day care was 11.3 per week, care at home by someone other than a parent averaged 9.6 hours a week, and care in someone else's home (which could include a family member, friend, neighbor, or licensed care provider) averaged 11.7 hours a week.
The researchers found that the more time a child spent in day care, the heavier the child was. Benjamin said there didn't appear to be a critical cut-off period, but that the relationship was linear, with weight rising as the number of hours spent in day care increased.
But when they further analyzed the data, they discovered that this relationship was only significant when care was provided in someone else's home, and that it wasn't an issue when care was provided in the child's home or at a day-care center.
The growth charts used in the study were from the U.S. Centers for Disease Control and Prevention, which pediatricians commonly use to assess a child's height and weight, and which take into account the child's age. Benjamin explained that if two infants had started in the 50th percentile of weight for their height and age, that the one who was cared for at home or in a day-care center would likely stay in the 50th percentile, while the one cared for in someone else's home would probably jump to the 55th percentile in weight.
One factor that might play a role, said Benjamin, is activity. While parents might not think about activity for an infant, even just getting out of the crib and having supervised tummy time can be activity for an infant.
"Parents often ask me when they need to get concerned about their child's weight, and I tell them before the child is born," said Dr. Goutham Rao, clinical director of the Weight Management and Wellness Center at Children's Hospital of Pittsburgh. "Being healthy during pregnancy and planning for breast-feeding are important, and this study shows you need to have some pretty strict rules for caregivers. Put limits on TV time, no sweet beverages and make sure infants have enough space to crawl around and eventually walk. Also, make sure they don't start solids too soon. Caregivers should maintain a stimulating environment with no TV, and toys or something for babies to move toward."
Benjamin said that "parents can be advocates and child-care providers are generally really open to suggestions. They're usually looking for ways to provide better care," she said.
SOURCES: Sara Benjamin, Ph.D., M.P.H., R.D., postdoctoral research fellow, department of population medicine, Harvard Medical School and Harvard Pilgrim Health Care, Boston; Goutham Rao, M.D., clinical director, Weight Management and Wellness Center, Children's Hospital of Pittsburgh; August 2009 Pediatrics