The study by Sunmin Lee, Sc.D., of the Harvard School of Public Health
and Harvard Medical School and colleagues found that women who cared for
grandchildren at least nine hours a week had a 55 percent increased risk
of heart attack.
“In comparison to women not providing child care,” Lee says, “providing
care to grandchildren nine hours or more per week was associated with
a significantly increased risk of coronary heart disease even after control
for a number of potential confounders.”
The study appears in the November issue of the American
Journal of Public Health.
Lee and colleagues gathered data from 54,412 women responding to the Nurses
Health Study, a continuing investigation of the health of female registered
nurses in the United States begun in 1976. The nurses answer questionnaires
every two years about their health status and risk factors.
The researchers based their study on information from
the 1992 Nurses Health Study survey, following the women until 1996.
They excluded anyone
who had been diagnosed with heart disease, stroke or cancer by 1992.
During the next four years, 321 heart attacks occurred among the all nurses.
After
statistical adjustment for other factors, Lee’s team determined
that caring for grandchildren more than nine hours a week or for children
more
than 21 hours a week increased the risk of heart disease.
Other researchers had suggested previously a “second-shift” hypothesis — that
the combined burden of a day’s work and the need to care for children
afterward produces added stress that may lead to poor health. Also, the
well-known Framingham Heart Study found rates of heart disease almost three
times higher among working women compared to housewives. Lee’s
study, however, failed to confirm those findings.
“Analyses by working status demonstrated that women who were not
working and provided care to grandchildren had a greater relative risk
than women who worked and provided care to grandchildren for the same amount
of time,” Lee says.
This study was not designed to find the reasons accounting for the association
between caring for grandchildren and heart disease. Other studies have
shown that caregiving grandmothers were more likely to be classified as
depressed, compared to non-caregivers. Lee speculates that these women
simply may not have the time to take care of themselves.
“It is possible that women — especially grandmothers — with
high levels of child-care demands have less opportunity to engage in their
own self-care and in preventive health behaviors,” he says.
