The researchers say that statins are highly prescribed for older women, but there are few clinical trials looking at how they affect this group.
The research - by a team at the University of Queensland (UQ) in Brisbane, Australia - is published in the journal Drugs & Aging.
The study finds that among a group of more than 8,000 women aged 75 and over, those taking statins had a 33 percent higher chance of being diagnosed with new-onset diabetes.
Lead author Dr. Mark Jones, of the UQ School of Public Health, says that statins are highly prescribed for this age group, but there are few clinical trials studying how they affect older women. "The vast majority of research is on 40- to 70-year-old men," he notes.
Statins are a class of drug designed to lower blood cholesterol, most of which is made in the liver.
They reduce liver production of cholesterol and also help the liver to remove cholesterol from the blood.
While the body needs cholesterol, if there is too much of it in the blood it can lead to buildup of plaque in the walls of arteries, which is a risk factor for stroke and heart disease - the leading cause of death for men and women in the United States.
Statins are the most recommended for lowering cholesterol
Treatment for preventing or reducing unhealthy cholesterol levels often start with changing diet and increasing physical activity.
Fast facts about statins
- The use of statins to lower cholesterol began in 1987
- In the U.S., both men and women are increasingly taking statin drugs
- People with liver disease should not take statins.
For some people, dietary and lifestyle changes may be enough to keep their cholesterol levels in check, but for others, medication may be needed - especially if they have other risk factors for heart disease.
There are several medications that can lower cholesterol in the blood. However, because they are the only cholesterol-lowering drug that has been directly linked to a reduced risk of heart attack and stroke, statins are the ones most recommended for patients, according to the American Heart Association.
From 1988-1994 to 2005-2008, there was a 10-fold increase in statin use by people aged 45 and over in the U.S. Over this period, there was also a corresponding drop in people with high cholesterol, which may or may not be due to increased use of statins and other cholesterol-lowering drugs.
However, a 2015 report from the Centers for Disease Control and Prevention (CDC) concludes that fewer than half of people in the U.S. eligible to take cholesterol-lowering medications are taking them.
Dose-response relationship between statins use and diabetes
The women were free of diabetes at the start of 2003, and the team assessed statin exposure based on prescriptions dispensed between 2002 and 2013.
Over the 10 years of follow-up, the team found that 49 percent of the women had filled prescriptions for statins and 5 percent had begun treatment for new-onset diabetes.
Statistical analysis revealed that statin exposure was linked to a 33 percent higher risk of developing diabetes. The risk increased with dose of statin - up to 51 percent for the highest dose.
Dr. Jones says that he and his team were most concerned to find this dose-response effect between statin use and risk of diabetes, especially as, "over the 10 years of the study most of the women progressed to higher doses of statins."
He concludes that doctors and their elderly female patients should be aware of these findings, and urges:
"Those elderly women taking statins should be carefully and regularly monitored for increased blood glucose to ensure early detection and management of diabetes."