WASHINGTON Parents worried about putting very young children into daycare got some reassuring answers on Friday -- children who have high-quality care see academic benefits lasting into high school.
The latest results from the long-running U.S. National Institutes of Health study show children in high-quality childcare scored slightly higher on measures of academic and cognitive achievement years later as teenagers.
They were also slightly less likely to act out than peers who were in lower-quality childcare, the researchers reported.
But children who spent the most hours in childcare had a slightly greater tendency toward impulsiveness and risk-taking at age 15 than teens who had spent less time in childcare, the researchers wrote in the journal Child Development.
Quality for childcare is usually measured by how much time the provider spends interacting with the children, as well as warmth, support and cognitive stimulation.
The ongoing study is meant to inform the policy debate on whether both parents should work when children are young and whether providing childcare is good for the children, their parents and society as a whole.
"High quality child care appears to provide a small boost to academic performance, perhaps by fostering the early acquisition of school readiness skills," said James Griffin of the National Institute of Child Health and Human Development, the NIH institute that paid for the study.
"The current findings reveal that the modest association between early childcare and subsequent academic achievement and behavior seen in earlier study findings persists through childhood and into the teen years."
Deborah Lowe Vandell of the University of California, Irvine, and colleagues tracked 1,364 children who have been studied since they were 1 month old starting in 1991.
They measured the quality, hours and type of daycare, collected results of standardized tests and interviewed the teens, their families and their schools. The children were from diverse backgrounds.
'THE IMPORTANCE OF INTERACTION'
Vandell's team found more than 40 percent of the children were given high-quality care and 90 percent spent at least some time in the care of someone other than a parent before age 4.
"These results underscore the importance of interaction between children and their daytime caregivers," she said in a statement. "We're seeing enduring effects of the quality of staff-child interaction."
But too much interaction may be harmful, researchers found in a second study.
Megan Gunnar of the University of Minnesota and colleagues studied 150 3- and 4-year-olds in 110 different family childcare homes.
About 40 percent of the children had elevated levels of a stress hormone called cortisol, they reported in Child Development.
Cortisol went up in children whose care providers were intrusive or overcontrolling -- measured by how much free play they had versus structured activities led by the providers that mainly involved rote learning.
Girls with larger increases in cortisol acted more anxious and vigilant at child care, while boys acted more angry and aggressive, Gunnar reported.
(Reporting by Maggie Fox; Editing by John O'Callaghan)