It’s a troubling fact: Women with diabetes have it worse, on average, than men with diabetes. This shocking inequality was revealed in a 2007 study that found that, between 1971 and 2000, death rates fell for men with diabetes, while rates for women with the disease didn’t budge. Plus, while men with diabetes live 7.5 years less on average than those who don’t have the disease, among women the difference is even greater: 8.2 years.

Why the disparity? It’s most likely a combination of factors, according to the 2007 study in Annals of Internal Medicine. For starters, the bodies of men and women are of course not the same, so differences in physiology are almost certainly involved. In addition, research has suggested that, as a group, doctors treat men and women differently. That gap in care leads to poorer outcomes for women and can even be downright deadly.

The Female Predicament
In the general population, women live longer than men, largely because of their lower rates of heart disease. Yet, when women get diabetes, something happens that strips them of this advantage. “The risk for heart disease is six times higher for women with diabetes than those without,” says Marianne Legato, MD, FACP, director of the Partnership for Gender-Specific Medicine at Columbia University. With men, diabetes increases the risk for heart disease two- to threefold. Data also show that women with diabetes are more likely than men with the disease to have poor blood glucose control, be obese, and have high blood pressure and unhealthy cholesterol levels.

What compounds the female predicament is that heart disease is more deadly in women with diabetes than it is in men with the disease. A 2007 study published in the European Heart Journal found that the association between diabetes and death by heart failure was stronger for women than it was for men. A Finnish study also found that in people with diabetes, heart attacks are more often fatal for women than they are for men. “For an older woman with diabetes, if she has a heart attack, it’s a big deal,” says Deborah Wexler, MD, MSc, an endocrinologist at Massachusetts General Hospital.

This greater risk, Wexler says, may stem in part from biological differences in how women and men experience heart attacks. For both, the most common warning sign of a heart attack is chest pain or discomfort in the upper body. However, women are more likely than men to experience only nausea, shortness of breath, and back or jaw pain during a heart attack. If a woman experiences these but doesn’t recognize them as heart attack warning signs, she may not seek treatment, lowering her chances of recovery.

Another diabetes complication, kidney disease, is also worse for women than men. In general, men have a higher risk for kidney disease, but that distinction again disappears with the appearance of diabetes. “Kidney disease generally doesn’t affect women until they get to menopause,” a time when estrogen levels fall and women, at least hormonally speaking, become more like men, says Christine Maric-Bilken, PhD, associate professor at the University of Mississippi Medical Center. “Yet, women with diabetes are just as likely to get kidney disease as men regardless of age.”

Depression is about twice as common in women as it is in men, and may take a greater toll on women with diabetes than on men with the disease. A landmark 2010 study of women in Archives of Internal Medicine suggested that depression increases the risk of diabetes and vice versa. Other research has shown that women with both conditions are twice as likely to die early as women who have neither diabetes nor depression. These studies didn’t look at men, but a 2006 study in the journal Public Health did, finding that diabetes and depression are associated in women, but not in men.

Biology or Psychology?
The greater toll that diabetes takes on women is likely to be caused, at least in part, by biology. Legato speculates that HDL (“good”) cholesterol, which is normally higher in women than men, may be behind the gender disparity. “When you get diabetes, the high triglycerides [blood fats] drive down HDL levels in women,” Legato says. “They’re like a seesaw.” And the combination of high triglycerides and low HDL adds up to a greater risk of heart disease.

Maric-Bilken is studying whether the sex hormones estrogen and testosterone are the key to why women with diabetes are more vulnerable to kidney disease than men with diabetes. “Women with diabetes have less estrogen,” she says. “In diabetes, once you lose that estrogen, the testosterone creeps up [and] takes up the slack of estrogen.” Studies have indeed found that lower estrogen levels are associated with kidney disease, but it’s not known whether there’s a cause-effect relationship or exactly how the lack of estrogen may contribute to kidney disease. It’s also possible that high testosterone is to blame. If there is a sex hormone connection, Maric-Bilken says, perhaps women with diabetes could improve their kidney health if the balance between testosterone and estrogen were restored with hormone therapy. But more research is needed to validate such an approach.

There’s also evidence that women with diabetes may get less effective health care, a difference that would stem not from biology but from psychological or sociological factors. One problem, according to Wexler, is perception. Since women in general are less likely to have heart attacks than men, “a woman sitting in front of a doctor may not raise the same alarm bells as a man,” she says. But women with diabetes are in fact not less likely to have heart attacks.

The gender bias was apparent in a 2005 Diabetes Care study led by Wexler. It found that women with diabetes were less likely than men to receive medication for heart disease risk factors, such as high LDL (“bad”) cholesterol. “Women tend to be treated less aggressively than men for cardiovascular risk factors,” she says.

The experience of diabetes is sex-differentiated for other reasons, too. Men with diabetes are much more likely than those without to develop erectile dysfunction, hampering their sex lives. Women with diabetes may also have issues such as lack of libido due to the disease. They are more likely to have polycystic ovary syndrome (PCOS), which is a risk factor for diabetes and can result in fertility problems. When they do get pregnant, women with diabetes can have a harder time than those without. Diabetes also makes women more prone to urinary and vaginal infections.

Recommendations
So what’s a girl to do? Legato and a group of doctors published a list of recommendations in Gender Medicine in 2006. According to the authors, women with diabetes should be tested for heart disease risk factors, like high blood pressure or unbalanced blood fats, and treated aggressively.

They also recommended that health history related to female biology should be taken into account more seriously. For example, gestational diabetes and PCOS both raise the risk that a woman will develop type 2 diabetes, as well as other health problems. So women with a history of these disorders should be monitored extra carefully, the doctors suggested.

The most important take-home message may just be that women with diabetes need to watch out for themselves and that their doctors need to watch out for them. While biology is important, it isn’t everything. There are lifestyle choices women (and men) can make, like exercising regularly and eating well, to improve their health. Good communication with a doctor about the effect of diabetes on a woman’s health in particular is also important; doctor and patient should discuss whether medications are needed to get blood pressure and blood fat levels on target. It’s clear that women with diabetes have an extra burden to bear. And it’s just as clear that, male or female, people with diabetes can do a lot to be aware of these issues—and take care to get healthy.