(Reuters Health) - Women with a history of irregular menstrual
periods may have a higher risk of developing heart disease than do other
women, a new study suggests.
The study, which followed more than 23,000 Dutch women for a decade, found
that those who said they'd typically had irregular periods in the past were
28 percent more likely than women who reported regular monthly periods to
develop heart disease.
There was no increased risk seen among women who reported regularly long
menstrual cycles (30 or more days between periods) or regularly short cycles
(26 or fewer days between periods).
Despite their relatively higher risk, though, the large majority of women
with irregular periods did not develop heart problems during the study
period. Of the roughly 4,000 women who reported a history of irregular
periods, 150 were diagnosed with coronary heart disease over the next 10
years.
Just over 17,000 study participants reported having either regular monthly
periods (between 27 and 29 days) or regularly short cycles. Of those women,
530 developed coronary heart disease.
The women were 50 years old, on average, at the start of the study.
It's known that women with a condition called polycystic ovary syndrome (PCOS)
have higher risks of heart disease and type 2 diabetes than other women
their age. In that disorder, the ovaries produce higher-than-normal amounts
of male hormones and menstrual periods are irregular or completely absent.
The new findings suggest that even in the absence of PCOS, less-extreme
irregularities in the timing of menstrual periods may be related to heart
disease risk, according to the researchers, led by Dr. Gerrie-Cor M. Gast of
the University Medical Center Utrecht in the Netherlands.
The potential reasons, however, are unclear. Since estrogen is believed to
have a generally protective effect on the heart and arteries -- and PCOS is
marked by hormone imbalance -- Gast's team measured hormone levels in a
subgroup of their study participants.
They found no evidence that altered hormone levels explained the association
between irregular periods and heart disease risk. Nor did factors such as
body weight, high blood pressure, or high cholesterol account for the link.
Both PCOS and very long menstrual cycles -- at least 40 days between periods
-- have been linked to increased risks of type 2 diabetes, which is a heart
disease risk factor.
In this study, women with irregular periods tended to have a higher risk of
type 2 diabetes than those with monthly periods; however, the association
was not statistically significant -- meaning the finding may have occurred
by chance.
More research, according to Gast's team, is needed to confirm the current
findings, and to uncover the underlying reasons for the link. The authors,
who could not be reached for comment, do not address what, if anything,
might lower the risk of heart disease among women with irregular cycles,
should these results hold up in future studies.
SOURCE: here(10)00505-4/abstract Fertility and Sterility, online May 7,
2010.
