For researchers investigating overall heart disease risk, a recently-published study suggests a new factor should be taken in account – gains in abdominal fat during menopause. This risk factor was significant even in women who remained the same weight, but had increased adiposity in the abdomen, meaning that BMI and weight measurements might not provide a clear enough picture of heart disease risk in postmenopausal women.
 
The study, which was led by the University of Pittsburgh’s Graduate School of Public Health and published in the journal Menopause, yielded a quarter-century of data collected on hundreds of women, and its authors suggested 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 BMI, which is a calculation of merely weight and height.
 
“We need to shift gears on how we think about heart disease risk in women, particularly as they approach and go through menopause,” senior author Samar El Khoudary, PhD, MPH, associate professor of epidemiology, said. “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 colleagues analyzed data sourced from 362 women in the Pittsburgh and Chicago area who participated in the SWAN heart study, who had an average age of 51 and had their visceral adipose tissue 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. 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.
 
Visceral abdominal fat is related to a greater secretion of toxic molecules that can be harmful to cardiovascular health. “Almost 70% of postmenopausal women have central obesity – or excessive weight in their midsection,” Saad Samargandy, PhD, MPH, who was a doctoral student at the time of the research, said. “Our analysis showed an accelerated increase of visceral abdominal fat during the menopausal transition of 8% per year, independent of chronological aging.”
 
Because of the technical challenges with measuring abdominal fat by CT scan, El Khoudary suggests that regularly measuring and tracking waist circumference would be a good proxy to monitor increases in abdominal fat. Measuring weight and BMI score alone could miss abdominal fat growth because of the variability of fat distribution across women.
 
“Historically, there’s been a disproportionate emphasis on BMI and cardiovascular disease,” she said. “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.”
 
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.
 
However, more research is needed to determine if certain diet, exercise, or lifestyle factors are more effective than others in combating growth in waist circumference, as well as whether there is a clear cutoff point at which waist circumference becomes concerning for heart disease risk.