| |
|
Headlines:
|
 |
Back to Gynecology Articles
Friday, 12th November 2004
|
|
|
|
|
Results from the Nurses' Health Study suggest prolonged preventive effect of breastfeeding and link irregular menstrual cycles to increased risk of disease.
|
|
| |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Rheumatoid arthritis (RA), an inflammatory disease of the immune
system, is between two and four times more likely to strike women
than men. Among women, RA is more likely to develop when
reproductive hormonal levels are changing, such as in the first few
months following a pregnancy and around the time of menopause.
Although previous researchers have studied this topic, the
relationship between hormones and the risk of developing RA remains
unclear.
Seeking more conclusive evidence, a team of researchers led by
Elizabeth Karlson, M.D. at Brigham and Women's Hospital in Boston
drew on a large sample – 121,700 women – to explore the contribution
of hormonal factors occurring prior to the onset of RA and the
impact of postmenopausal hormone replacement therapy on the risk of
disease. Their findings, published in the November 2004 issue of
Arthritis & Rheumatism, strongly support the lasting benefits of breastfeeding in protecting
against the disease. What's more, the researchers identified a new
risk factor for RA: irregular menstrual cycles.
The study's subjects were all women enrolled in the Nurses'
Health Study, a sweeping investigation of disease, health, and
lifestyle, ongoing since 1976. Through extensive questionnaires, the
research team documented each woman's reproductive history with
attention to potential RA risk factors, including age at menarche,
age at first birth, history of breastfeeding, use of oral
contraceptives, and regularity of menstrual cycles and in older
women studied the use of estrogen after menopause. Among these
women, the researchers confirmed 674 RA patients, diagnosed anywhere
between 1976 and 2002. Most of the women were middle-aged at disease
onset; the mean age was 56 years.
Upon analyzing the data, adjusting for variables such age and
cigarette smoking, the researchers noted several interesting trends.
One of the strongest was a decreasing risk of RA with increasing
duration for breastfeeding. Looking at total lifetime breastfeeding,
regardless of number of children, women who had breast-fed for
between 13 and 23 months had a 20 percent reduction in the risk of
RA compared with women who did not breastfeed. Women who had
breast-fed for at least 24 months – two full years out of their
childbearing years – increased their risk reduction to 50 percent.
"Our data suggest breast-feeding confers long lasting protection
against developing RA," Dr. Karlson states, "because the mean time
since the last pregnancy among women with RA was 25 years." In
addition, women who experienced irregular menstrual cycles between
the ages of 20 and 35 were shown to have an increased risk of
subsequent RA. Women who had begun menstruating at an early age, 10
or younger, were more likely to develop seropositive RA. The study's
results did not show any association between a history of oral
contraceptive use and disease risk, or any significant differences
in disease risk related to a woman's number of pregnancies.
Focusing on the sample of RA patients, compared to women who did
not develop RA, the researchers confirmed that the risk of RA
increases with age and demonstrated a peak risk at the typical time
of menopause, age 50 to 54. Because the onset of RA often coincides
with menopause, some studies have linked the disease to falling
estrogen levels, indicating the potential benefits of estrogen
therapy. In this study, however, estrogen therapy among
postmenopausal women did not protect against RA. "These findings
suggest avenues for further research into the hormonal mechanisms
involved in RA, because the complex relationships between RA and
reproductive hormones clearly warrant further study," Dr. Karlson
concludes.
Sources:
Elizabeth W. Karlson, Lisa A. Mandl, Susan E. Hankinson, Francine
Grodstein. Do breast-feeding and other reproductive factors
influence future risk of rheumatoid arthritis?: Results from the
Nurses' Health Study. Arthritis & Rheumatism, Volume 50, Issue 11 (p
3458-3467).
|
|
|
|
Are you a doctor or a nurse?
Do you want to join the Doctors Lounge online medical community?
Participate in editorial activities (publish, peer review, edit) and
give a helping hand to the largest online community of patients.
Click on the link below to see the requirements:
Doctors Lounge Membership
Application |
|
|
|
send
to a friend
printer
friendly version
