Why diabetes is a greater heart health risk for women than men

 

Diabetes is a major risk factor for heart disease in both men and women. However, it has a greater impact on women’s heart health than men’s.

“Diabetes appears to be a stronger risk factor for cardiovascular events in women than in men,” says endocrinologist Dr. Lorraine Lipscombe, director of the Centre for Integrated Diabetes Care at Women’s College Hospital. “If you compare cardiovascular events in women who have diabetes versus women who don’t have diabetes, the spread is greater than it is between men with diabetes and men without diabetes.”

Dr. Lipscombe explains that in all populations, including populations with diabetes, women have a lower rate of heart attacks than men. However, when a woman gets diabetes, it narrows that gender gap: relative to women who don’t have diabetes, her risk is greatly increased. In comparison, when a man gets diabetes, it does increase his cardiovascular risk compared to men without diabetes, but not to the same extent as it would for a woman.

While there are many other possible complications of diabetes – such as kidney disease and eye disease – cardiovascular disease is one of the most serious, and the one most often linked to mortality. Researchers aren’t certain why diabetes affects women’s heart health more dramatically than men’s, but there are a number of factors that may play a role.

“Women may have fewer other risk factors for heart disease,” Dr. Lipscombe says. “Men may have higher rates of cardiovascular risk factors such as smoking or hypertension, but for women, diabetes might be their biggest risk factor for heart disease.”

Another possible factor is the difference in how heart risks are managed in men and women. Research has shown that women get less aggressive treatment than men do for heart disease, and for heart disease risks.

“Women are less likely to be given cholesterol lowering treatment. They may have less aggressive treatment for their blood pressure,” Dr. Lipscombe says. “One reason for that might be if they’re young and they’re of reproductive age, many doctors are reluctant to give them medications that may affect an unborn child if they get pregnant. So women who have diabetes at reproductive age are less likely to get all those risk-reducing treatments because of the concern that it’s going to affect a pregnancy.”

Differences in heart symptoms may also contribute. Cardiovascular disease may present differently in women and men, which may result in delayed diagnosis in women. The type of nonspecific symptoms that women may be more likely to have – such as chest discomfort, upper back pain or unusual fatigue – make it less likely that they will seek medical treatment. If they do seek treatment, their symptoms may not be immediately recognized as cardiovascular.

“Therefore once they present, they are at a more advanced stage of disease,” Dr. Lipscombe says.

Women may also be diagnosed at a later stage of diabetes than men, with a more advanced risk profile for complications, including heart disease.

There is also some evidence that the adverse effects of high blood sugar – the defining feature of diabetes – may be more harmful in women than men.

“There are some interesting data suggesting that when a woman is exposed to high blood sugar, she might incur more damage than men for the same level of high blood sugar,” Dr. Lipscombe says. “So women with diabetes may be more vulnerable to the effects of diabetes on their hearts and their vasculature than men.”

Recognizing the greater burden of cardiovascular disease risk in women with diabetes offers opportunities to address that gap.

“We need to give greater attention to cardiovascular risk management and modification – such as more aggressive risk management – for women with diabetes,” Dr. Lipscombe says. “We need to have earlier identification of high risk groups for diabetes and cardiovascular prevention.”

Those high-risk groups include women with polycystic ovary syndrome (PCOS), and women who have had gestational diabetes. Having PCOS multiplies the risk of developing Type 2 diabetes by three to five times. Gestational diabetes multiplies Type 2 diabetes risk by seven to eight times, and also increases cardiovascular risks.

Dr. Lipscombe and fellow Women’s College researchers are currently conducting a randomized controlled trial of a program designed to reduce Type 2 diabetes risk in women who have had gestational diabetes. The ADAPT-M study (Avoiding Diabetes After Pregnancy Trial in Mothers) is comparing outcomes of a six-month customized lifestyle coaching program to standard care.

“With this study, we’re trying to lower diabetes risk in new mothers who have had gestational diabetes,” Dr. Lipscombe says. “ADAPT-M is a way to address the trend of younger women developing more diabetes and obesity.”