According to the CDC, only about 55 percent of people who could benefit from taking a cholesterol medication are currently using one. Yet a study published in May 2019 in the journal Diabetes Metabolism Research and Review found that reducing the risk of a heart event with these drugs could come at a cost: an increased risk for developing type 2 diabetes. “Our findings suggest that more research is needed to better understand the biologic changes that take place when patients take statins,” says Victoria Zigmont, PhD, assistant professor of public health at Southern Connecticut State University in New Haven and lead author of the study. Statins continue to be effective in preventing heart attacks and strokes, and if you’re taking a prescribed statin, don’t stop because of this study, says Dr. Zigmont, adding that ideally the findings would open further discussions about diabetes prevention and patient and provider awareness of the issue. RELATED: 10 Surprising Facts About Statins

Researchers analyzed 4,683 men and women who were employees and dependent spouses enrolled in a private insurance plan in the Midwest. Study authors conducted the research retrospectively, meaning they looked back at existing records to uncover any possible connections between statin prescriptions and diabetes. The average age of participants was 46; 62 percent of the group were female, 38 percent male, and 83 percent were white, 12 percent were black, and 4 percent were additional minority groups. Subjects had an average body mass index (BMI) of 30 to 31, which falls into the category of obese. At the start of the study, participants didn’t have diabetes; they were candidates for statins based on heart disease risk but had not yet started the medication. About 16 percent of the group — 755 patients — were eventually prescribed statins during the study period, which ran from 2011 until 2014. To determine if there was a link between statin use and diabetes, researchers controlled for several confounding factors, including gender, age, ethnicity, education level, cholesterol and triglyceride readings, BMI, waist circumference, and the number of visits to the doctor during the study period. Researchers found that statin users had more than double the risk of a diabetes diagnosis compared with those who didn’t take the drugs. Those who took the cholesterol-lowering drugs for more than two years had more than 3 times the risk of diabetes. The fact that taking the statin longer was associated with an increased risk of diabetes indicated a dose-dependent relationship, which indicates this is likely a causal relationship, says Zigmont. RELATED: How Heart Disease and Type 2 Diabetes Are Connected Yet Eugene Yang, MD, clinical associate professor of medicine at the University of Washington School of Medicine in Seattle, says this observational study may indicate an association between statin use and type 2 diabetes, but it does not show causality. “In studies where researchers have done randomized prospective clinical trials where incidence of developing diabetes risk was one of the secondary endpoints — and those trials are more scientifically rigorous than this one — this association has not been demonstrated,” says Dr. Yang. The HOPE-3 trial, published in May 2016 in The New England Journal of Medicine, was an international study that did not show any increased risk of developing diabetes with a statin, says Yang. There were several limitations to this study, which the authors acknowledge and that Yang notes. Individuals who filled a new prescription for statins 90 days into the study were classified as statin users, though study authors didn’t measure compliance throughout the study. They didn’t measure or include factors such as smoking, exercise, and alcohol use, which are all risk factors for diabetes. Prediabetes status was not available at the outset of the study, so some patients who were already at a high risk could have been included. RELATED: Is Prediabetes a Useful Diagnosis? A New Article Revives an Old Debate

For Many Patients, Research Shows the Benefits of Statins Outweigh the Risks

About 610,000 people die of heart disease every year, making it the leading cause of death in America, according to the CDC. Several conditions and lifestyle choices increase the risk of developing heart disease, including:

DiabetesOverweight and obesityPoor dietPhysical InactivityExcessive alcohol use

Currently, patients are undertreated due to both primary care physicians’ concerns and patients’ personal beliefs about these drugs, says Yang. “In the big picture, these drugs (statins) and treatments to lower cholesterol are really beneficial in reducing the risk of heart attack and stroke in the right high-risk population,” he says. Deciding which action or medicine to take or forgo is all about weighing the benefits and risks, says Yang. In the JUPITER trial, a study published in The New England Journal of Medicine that looked at the benefits and risks in statins and diabetes, authors concluded that 134 cardiovascular events were prevented by statin use for every 54 new cases of diabetes diagnosed. “As a cardiologist, I see the patients who have had heart attacks, strokes, and bypass surgery, and so my perspective is different,” he says. Many cardiologists take a more aggressive stance on treating heart disease because they see the downstream effect of inadequate management of these primary risk factors, says Yang. RELATED: Heart-Health Tips for Women in Their 20s, 30s, 40s, and Beyond

What Does This Mean if You’re Taking a Statin to Lower Cholesterol?

If you’re unsure whether a statin would benefit you, check with your healthcare team, says Yang. In certain situations — for example, in someone who’s at risk for cardiovascular events and looking to help prevent heart disease — where there’s a weaker level of evidence for statin use, he says. On the other hand, there’s enough scientific evidence in some higher-risk populations that show there are strong benefits to taking a statin, says Yang. To help his patients understand the risks and benefits, Yang shares the results of the 4S trial, an earlier study that looked at the statin simvastatin to see if treating cholesterol with a statin helped delay death. The absolute risk reduction in that trial was about 4 percent in cardiovascular mortality, says Yang. That means if you put 100 patients with coronary heart disease in a room and treat them with a statin, maybe one person will develop diabetes, but four people in that room will be saved from having heart attack, says Yang. “That’s the perspective people need to understand,” he says.