Women who experience an accelerated accumulation of abdominal fat during menopause are at greater risk of heart disease, even if their weight stays steady, according to a University of Pittsburgh Graduate School of Public Health-led analysis published today in the journal Menopause.
The study—based on a quarter century of data collected on hundreds
of women—suggests that measuring waist circumference during preventive
health care appointments for midlife women could be an early indicator
of heart disease risk beyond the widely used body mass index (BMI)—which
is a calculation of weight vs. height.
“We
need to shift gears on how we think about heart disease risk in women,
particularly as they approach and go through menopause,” said senior
author Samar El Khoudary, Ph.D., M.P.H., associate professor of epidemiology
at Pitt Public Health. “Our research is increasingly showing that it
isn’t so important how much fat a woman is carrying, which doctors
typically measure using weight and BMI, as it is where she is carrying
that fat.”
El Khoudary and her colleagues looked at data on 362 women from Pittsburgh and Chicago who participated in the Study of Women’s Health Across the Nation
(SWAN) Heart study. The women, who were an average age of 51, had their
visceral adipose tissue—fat surrounding the abdominal organs—measured
by CT scan and the thickness of the internal carotid artery lining in
their neck measured by ultrasound, at a few points during the study.
Carotid artery thickness is an early indicator of heart disease.
The team found that for every 20% increase in abdominal fat, the
thickness of the carotid artery lining grew by 2% independent of overall
weight, BMI and other traditional risk factors for heart disease.
They also found that abdominal fat started a steep acceleration, on
average, within two years before the participants’ last period and
continued a more gradual growth after the menopausal transition.
Saad Samargandy, Ph.D., M.P.H.,
who was a doctoral student at Pitt Public Health at the time of the
research, explained that fat that hugs the abdominal organs is related
to greater secretion of toxic molecules that can be harmful to
cardiovascular health.
“Almost 70% of post-menopausal women have central obesity—or
excessive weight in their mid-section,” said Samargandy, also the first
author of the journal article. “Our analysis showed an accelerated
increase of visceral abdominal fat during the menopausal transition of
8% per year, independent of chronological aging.”
Measuring abdominal fat by CT scan is expensive, inconvenient and
could unnecessarily expose women to radiation—so El Khoudary suggests
that regularly measuring and tracking waist circumference would be a
good proxy to monitor for accelerating increases in abdominal fat.
Measuring weight and BMI alone could miss abdominal fat growth because
two women of the same age may have the same BMI but different
distribution of fat in their body, she added.
“Historically, there’s been a disproportionate emphasis on BMI and
cardiovascular disease,” said El Khoudary. “Through this long-running
study, we’ve found a clear link between growth in abdominal fat and risk
of cardiovascular disease that can be tracked with a measuring tape but
could be missed by calculating BMI. If you can identify women at risk,
you can help them modify their lifestyle and diet early to hopefully
lower that risk.”
Late last year, El Khoudary led a team in publishing a new scientific statement for the American Heart Association
that calls for increased awareness of the cardiovascular and metabolic
changes unique to the menopausal transition and the importance of
counseling women on early interventions to reduce cardiovascular disease
risk factors.
El Khoudary noted that more research is needed to determine if
certain diet, exercise or lifestyle interventions are more effective
than others, as well as whether there is a clear cut-off point for when
growth in waist circumference becomes concerning for heart disease
risk.
Additional authors include Karen A. Matthews, Ph.D., Maria M.
Brooks, Ph.D., Emma Barinas-Mitchell, Ph.D., and Jared W. Magnani, M.D.,
M.Sc., all of Pitt; and Imke Janssen, Ph.D., and Rasa Kazlauskaite,
M.D., M.Sc., of Rush University.
This research was funded by National Institutes of Health
grants U01NR004061, U01AG012505, U01AG012535, U01AG012531, U01AG012539,
U01AG012546, U01AG012553, U01AG012554, U01AG012495, HL065581 and
HL065591.
PHOTO INFO: (click image for high res version)
PHOTO INFO: (click image for high res version)
CREDIT: University of Pittsburgh
CAPTION: Samar El Khoudary, Ph.D., M.P.H., associate professor of epidemiology, University of Pittsburgh Graduate School of Public Health