Here’s what doctors know about heart disease and menopause: Women tend to have heart attacks and heart problems about a decade later than men, on average, and experts have attributed that buffer period to the presence of estrogen. Once estrogen levels drop after menopause, heart disease rates start to climb. But in the latest research published in the Journal of the American Heart Association, researchers say that risk for heart disease actually starts to peak in the years before menopause, and the risk is especially great for African-American women.

“As much as conventional wisdom has been that it’s menopause itself, and being post menopausal, that increases heart disease risk, it appears that the time leading up to menopause is associated with more rapid change in heart risk factors,” says Dr. Mark DeBoer, associate professor pediatrics at University of Virginia, who, with his colleagues, studied 1,470 women over 12 years. “Once menopause is in place, there is a slower chance in these factors.”

Among African American women, these risk factors steadily increased in the years prior to menopause at a greater rate than for white women, suggesting that African-American women may be more vulnerable to the changes occurring prior to menopause.

The effect remained even after DeBoer adjusted for whether the women were taking hormone replacement or not. Doctors had thought that replacing declining levels of estrogen with supplemental hormone therapy would protect women’s hearts but a large trial in 2002 showed that the therapy increased risk of breast cancer and did not lower heart disease rates. Current guidelines suggest that women only take hormone therapy for a short period around menopause to alleviate symptoms of hot flashes and night sweats. The latest findings, however, leave open the question of what role, if any, estrogen is playing in the constellation of changing occurring during menopause and how that could affect risk factors for heart disease.

What the results do stress, however, is that this period is an important time for women to make lifestyle changes to lower their risk of metabolic syndrome effects—such as maintaining a healthy weight, and keeping cholesterol levels and blood pressure in check. “These data suggest that heart disease risk accelerates in the years just leading to perimenopause and menopause,” says DeBoer. “Knowing that there may be a more rapid increase in heart-related risk factors, women may be able to increase their level of exercise and the quality of their diet to in theory counteract some of this natural rise in heart disease risk.”

 

This article originally appeared on Time.com.