Being overweight
in young adulthood or later in life may raise a woman's
risk of ovarian cancer, particularly if she's never had
children, researchers have found. The study of more
than 2,100 women could be particularly worrisome for
lesbians, many of whom do not have children during
their lifetimes and who, studies have shown, are generally
heavier than their age-matched heterosexual peers.
In a study of
2,110 women with and without ovarian cancer, researchers
found that those who were relatively heavy, either in recent
years or at the age of 18, were more likely than
thinner women to develop the disease.
But the
relationship between weight and ovarian cancer was strongest
among women who'd never given birth. For them, cancer risk
climbed in tandem with recent body mass index (BMI), a
measure of weight in relation to height.
Among childless
women, those who were obese in recent years had 2.5 times
the risk of ovarian cancer compared with the thinnest women.
The same pattern emerged when the researchers looked
at the women's weight gain since age 18.
Julia Greer and
her colleagues at the University of Pittsburgh Medical
Center reported the findings in the journal Cancer. A
number of studies have looked at the relationship
between body weight and ovarian cancer risk, with
conflicting results. A connection is considered biologically
plausible because excess body fat can raise levels of
estrogen as well as male sex hormones called
androgens, which may in turn feed ovarian tumor
development.
Pregnancy and
childbirth are believed to lower the risk of ovarian cancer
by reducing the number of times a woman ovulates in her
lifetime and therefore reducing her estrogen exposure.
The new findings
suggest that in overweight women who've had no children,
the effects of excess body fat and "incessant" ovulation
combine to raise the risk of ovarian cancer, according
to the study authors.
Along with their
greater estrogen exposure, these women may develop
chronic inflammation in the ovaries as a result of
continuous ovulation, the researchers speculate. This
inflammation might then damage cells in a way that
leads to cancer.
The findings
offer yet another reason to maintain a healthy weight
throughout life, Greer said. And that goes for all women,
whether they've had children or not, she pointed out.
According to
American Cancer Society estimates, Greer noted, at least one
third of all cancer deaths in the U.S. each year are
attributable to excess weight and obesity. (Reuters,
with additional reporting by The Advocate)