Statin medications used by women after menopause appear to increase their risk of developing diabetes, according to a large, new study.
The research echoes findings of other studies linking the cholesterol-lowering drugs with an increased diabetes risk in men and women. Statins include drugs such as Lipitor, Lescol and Mevacor.
"We found statins increased the risk of diabetes about 48% after adjusting for different risk factors such as family history of diabetes, body mass index and [physical] activity," said Dr Yunsheng Ma, associate professor of medicine and an epidemiologist at the University of Massachusetts Medical School in Worcester, Mass. "It's a moderate risk," he said.
However, the study found an association, not a cause and effect.
The authors stressed that the findings are not a reason to change current guidelines for use of the drugs in those with or without diabetes. Statins are often prescribed to lower blood cholesterol levels in order to prevent heart disease or its progression. Diabetes is a strong risk factor for heart disease.
For the study, the researchers followed nearly 154 000 participants in the Women's Health Initiative, a long-running look at health issues in postmenopausal women.
At the study start in 1993, their average age was 63, and slightly more than 7% were taking statins. By 2005, more than 10 200 reported they had developed type 2 diabetes, meaning their blood sugar levels were too high.
People with type 2 diabetes don't make or properly utilise insulin, a hormone that regulates the amount of sugar, or glucose, in the blood. Uncontrolled diabetes can damage the kidneys, nerves and eyes.
Those taking statins were more likely to develop diabetes, the researchers found. When contributing factors such as family history and excess weight were considered, the statin users were nearly 1.5 times more likely to develop diabetes than those not taking statins. The risk applied for all kinds of statin drugs.
The researchers can't explain the link. "It's still an area under scrutiny," said Annie Culver, the study's first author and a consulting pharmacist with the University of Massachusetts Medical School.
"Statins may affect the way the body manages insulin and glucose responses," she said.
The take-home message for women and others, the researchers said, is to pay attention to lifestyle measures that can lower diabetes risk or help manage the disorder if they already have it. Keeping a healthy body weight, eating a healthy diet and getting regular physical activity can all help.
"If they do need statin therapy, they should not be complacent that medication will solve the problem," Culver said. Lifestyle measures still matter, she added.
If an older woman needs statins to reduce heart attack or stroke risk, this study should not dissuade them, agreed Dr Spyros Mezitis, a clinical endocrinologist consultant at Lenox Hill Hospital in New York City. He said the findings are observational, and as such the researchers cannot control for all the possible confounding factors.
Doctors should try to keep statin dosage as low as possible, he said. And women with and without diabetes who are prescribed a statin to lower cholesterol should expect regular monitoring of their cholesterol and blood glucose levels.
Dr Suzanne Steinbaum, attending cardiologist and director of Women and Heart Disease at the Heart and Vascular Institute at Lenox Hill Hospital, said that as a result of the findings, women on the medications should watch their intake of sugar, starches and carbohydrates to maintain healthy blood sugar levels.
Every woman taking statins needs to know her risk of heart disease, Steinbaum said, and she needs to ask her doctor, "Is the statin necessary?"
The researchers, who noted that statins can manage the heart-related consequences of diabetes, said more work is needed to unravel the link between the drugs and the blood-sugar disorder.
(HealthDay News, Kathleen Doheny, January 2012)