Oversize waistlines are a potent risk factor for heart disease in women

Sep 24 2008

A heart expert at Johns Hopkins is calling for all women with a waistline measuring more than 35 inches to get an annual check-up and detailed risk assessment for heart problems because excess abdominal fat, even in the mildly obese and overweight, leads more than a third of women to underestimate their lifetime risk of having a heart attack, stroke or chest pain (angina).

Cardiologist Erin Michos, M.D., M.H.S., who plans to make her pitch Sept. 23 directly to colleagues during a special lecture at The Johns Hopkins Hospital, says the recommendation is based on a national, multicity screening of 8,936 women, ages 35 to 63, for heart disease risk factors. The screening, she says, found a strikingly high number of overweight American women whose stretched girth was tied to a serious underestimation of risk using traditional tools to assess heart health.

In a report published in the August issue of the Journal of Women's Health, the research team showed that 39 percent of women screened were overweight (having a body mass index between 25 and 30) and 35 percent were obese (having a body mass index over 30, often overweight by more than 30 pounds.) And when waistlines 35 inches and larger were factored into the risk assessment, 55 percent of these women were found to have hearts at increased risk of disease.

"It is time for physicians and patients to pull out their measuring tapes and for overweight women in particular to start shedding some pounds," says Michos, an assistant professor at the Johns Hopkins University School of Medicine and its Heart and Vascular Institute.

She points out that traditional risk-factor scoring leaves out waist size, taking into account only such other factors as age, blood pressure, blood cholesterol levels, smoking and diabetes. These measures have long been used as part of the Framingham Risk Assessment, which only assesses people's 10-year risk of heart disease.

But the team's latest assessments - drawn from a 2006 annual public screening in 14 communities across the United States, in which women were asked to undergo a short physical check-up and fill out a health questionnaire - changed significantly when expanded waistlines were factored into their calculations.

More than half (59 percent) of the 85 percent of women originally thought to be at low risk of heart trouble were now found to have one or two additional risk factors. And 19 percent of those at low risk and nearly half (41 percent) of the women originally ranked at intermediate risk actually had three or more previously unknown risk factors.

"These women have a high lifetime risk of cardiovascular disease even though their 10-year risk may be predicted as low," says Michos, who points out that the presence of a single, major risk factor for heart disease by the age of 50 cuts back on women's median lifespan compared to women with no risk factors.

"Our results really emphasize the growing epidemic of obesity in America and showcase its potential for misreading or masking future harm to women's heart health," she says. "Even if they are not experiencing immediate problems, they could soon be in trouble. Overweight people are more likely to develop risk factors that lead to cardiovascular problems, such as high blood pressure, blood sugar imbalances and excess blood lipid levels. And the reverse is also true: Losing weight, especially abdominal fat, is the first step in lowering blood pressure and getting blood cholesterol levels under control."

Michos notes that other research has shown a loss of just five pounds lowers people's risk of pre-diabetes by 31 percent. Losing 10 pounds lowers blood pressure by 5 millimeters of mercury.

Michos says she has started her campaign with local physicians because it will take a few years to amass the necessary additional evidence to change national clinical guidelines. Results from the 2007 screenings, coordinated by the Maryland-based Sister to Sister, Everyone Has a Heart Foundation, will not be ready until later this year.

"Physicians and others have unfortunately become too accustomed to seeing heavy- set people, and there is a risk that we overlook or dismiss being overweight and obesity as a potential and future source of heart problems," says Michos. "Even if the problems are not evident now, it is more important to start screening women at a younger age to forego heart problems later in life.

"Community screening events have confirmed that many women are unaware of their risk factors and the screenings have proven effective at identifying those women at risk and, hopefully, we will be able to expand these programs in the future," she adds, noting that 48 percent of women with high cholesterol levels were newly diagnosed with the condition, as were 7 percent of women with hypertension. "Awareness is the first step to implementing heart-healthy lifestyle changes to reduce their risk," says Michos. The next Sister to Sister community screening event will take place in February 2009.

Furthermore, Michos says annual survey results, though specific to women, also bear significance for men, for whom a waistline greater than 40 inches is considered obese.

Researchers say their next steps are to monitor screened women to see how well follow-up treatments worked at not only lowering risk, but also in lowering actual heart problems and whether or not this stretches out lifespan.

Of 150 women who were screened as high risk in 2006, 71 percent followed up with a visit to their physician, 64 percent changed diet, 47 percent lost weight, 61 percent monitored their blood pressure levels, 6 percent stopped smoking, and 23 percent checked their waistline against the 35-inch benchmark.

According to the latest statistics from the American Heart Association, one in three American women has some form of cardiovascular disease. Sixty-nine million women are overweight, including more than 36 million who are obese.

Funding for this study was provided by the Sister to Sister, Everyone Has a Heart Foundation. Besides Michos, other researchers from the Johns Hopkins Ciccarone Preventive Cardiology Center involved in this study and the Sister to Sister annual screenings were Brian Kral, M.D., M.P.H.; Catherine Campbell, M.D.; M. Dominique Ashen, Ph.D., C.R.N.P.; and Roger Blumenthal, M.D. Other researchers included Irene Pollin, Ph.D., M.S.W., and Laurene McKillop, Ph.D., from Sister to Sister; Teresa Shattuck, Ph.D., Michele Debarthe Sadler, Ph.D., and Karen Boyle, Ph.D., from Shattuck & Assoc.; Khurram Nasir, M.D., M.P.H., from Massachusetts General Hospital in Boston; Rita Redberg, M.D., from the University of California San Francisco; and Karlynn Brintzenhofeszoc, Ph.D., M.S.W., from Catholic University of America in Washington, D.C.