Children who spend more time being cared for by someone other than their mothers in the first three years of life have slightly less positive interactions with their mothers than young children who spend little or no time in day care or with a babysitter, according to results released yesterday of a federally funded study of nearly 1,300 children.

The study, funded by the National Institute of Child Health and Human Development and conducted at 10 sites around the country, is sure to further inflame the debate about the quality and impact of child care in the United States. The mothers of the majority of American children under the age of 1 work outside the home.

To gauge the impact of this shift in the role of mothers, which has accelerated in the past 10 years, researchers videotaped and then rated the quality of brief interactions between mothers and children at the ages of 6, 15, 24 and 36 months. They found that the children who spent more than 10 hours per week being cared for by someone other than their mothers had "somewhat less positive interactions" with their mothers than those who spent most or all of their time with their mothers.

At the same time, noted Margaret Tresch Owen of the University of Texas, who coordinated the study, the mother's level of education was a better predictor of sensitive interaction than either the length of time in child care or the quality of that care. Mothers with higher incomes and more education tended to use higher quality child care and to be more sensitive with their children, researchers found.

"We only find that working more hours is related to less sensitivity when we compared mothers with similar levels of education and income, but not when we compare mothers regardless of their education and income," said Margaret Burchinal, a psychologist at the University of North Carolina and director of the study's design.

Owen cautioned against reading too much into the overall results of the study, which were published in the November issue of the journal Developmental Psychology. "It's really a small effect, very modest, but it was consistent," she said. "And it was not modified by the quality of care" or whether care was provided in a relative's home, the child's home or a day care center.

Owen said that "as a parent, I would take these findings not as bad news, but as encouragement to me to maximize the time I spend with my very young children."

--Sandra G. Boodman


Healthy older people produce just as much of the sleep hormone melatonin as young people, suggests a study funded by the National Institutes of Health.

"We never anticipated the result we found," said Charles Czeisler of Harvard Medical School, lead researcher of the study published last Friday in the American Journal of Medicine. "The conventional wisdom was that melatonin levels decline with age."

Melatonin is a natural hormone produced by the pineal gland deep in the brain. It is produced at high levels during a person's normal sleeping hours.

The study's review of whether aging causes a decrease in melatonin production is important since so many older Americans have sleeping problems--and many take melatonin supplements, said Andrew Monjan of the NIH's National Institute on Aging.

This study "clearly shows sleep problems in older people cannot be explained primarily on the basis of melatonin decreases with age," Monjan said.

The study compared 34 healthy older men and women, ages 65 to 81, with 98 men ages 18 to 30. Unlike many previous studies, this one carefully controlled for factors that could artificially lower melatonin levels, including exposure to light, varying sleep-wake times and drugs commonly used by the elderly.

The research is important because no one knows how safe the chronic use of melatonin supplements is, especially in the large doses typically sold, Monjan said. Among other possibilities, some studies suggest high-dose melatonin may constrict blood vessels in the brain and risk stroke.

--Associated Press


A Baltimore-based prevention program that helped first graders learn to control aggression resulted in less antisocial behavior by the time they reached middle school and lower rates of cigarette smoking, according to a study from the Johns Hopkins School of Public Health.

This research is part of a larger, ongoing study led by Sheppard G. Kellam, professor of mental hygiene at Johns Hopkins, and sponsored by the National Institute of Mental Health, to assess effects of early prevention programs in reducing risky behavior, such as substance abuse and antisocial behavior. The researchers looked at 678 first-graders from nine Baltimore public schools. Slightly more than half of the children were boys. Nearly two-thirds of the youngsters in the study received either free lunch or a subsidized lunch, which placed them among the lowest family income levels.

The research team introduced a behavior management strategy designed to reduce aggressive behavior into half of the classrooms and used the other half as a control group. Both groups were then followed through middle school.

The study found that participants who received behavior management instruction in first grade were significantly less likely to start smoking or to engage in antisocial behavior compared with the control groups.

The findings, published in the fall issue of the American Journal of Community Psychology, show that "classroom management is incredibly important," Kellam said.

--Sally Squires