It’s been known for a while that statin medications like Lipitor may be related to an increased risk of developing type-2 diabetes. A new study shows that increase may have something in common with the lower risk of diabetes found in persons with genetically-acquired high cholesterol.

The study was published in March 2015 in the Journal of the American Medical Association. Researchers studied the contents of a database that has tracked over 63,000 persons for familial hypercholesterolemia as part of a Dutch screening program that ran from 1994 to 2014. Researchers found those persons with familial hypercholesterolemia were 51 percent less likely to develop type-2 diabetes than their relatives who did not have the same disorder.

Researchers theorize that genetic predisposition to high cholesterol may have something to do with why statins increase the risk of type-2 diabetes. Statins lower LDL – low-density lipoprotein, or bad cholesterol – by activating LDL receptors.

The problem may be that the pancreas, which has a role in controlling blood sugar, has a lot of those receptors. Researchers think that activation of the LDL receptors in the pancreas may damage that organ, thereby harming blood sugar control.

The researchers say that risk factors for Lipitor diabetes include hypertension and being overweight. Persons with diabetes risk factors like these are the ones who should be cautious about therapy with Lipitor or other statins, they say. Those who are not already at risk for developing diabetes do not face as great a risk of developing Lipitor diabetes.

While persons with familial hypercholesterolemia enjoy a lower risk of type-2 diabetes, they still bear the higher risk for heart disease and stroke that comes with high cholesterol.

Lipitor, also sold under the generic name atorvastatin, has been on the market since it was first approved by the FDA in December 1994. Lipitor is made and distributed by Parke-Davis, a division of Pfizer, Inc.

Sales of Lipitor continue to excel. The drug yielded $7.7 billion in U.S. sales alone in 2011, making it the top-selling prescription drug that year.

Some studies show Lipitor may be related to an increased risk of developing type-2 diabetes, particularly in post-menopausal women. A study from 2012 evaluated the instance of diabetes in over 150,000 women between the ages of 50 and 79 who took statins like Lipitor. The study found a 48 percent increase in the risk of developing diabetes. Asian women were deemed most at risk, as were those with a healthy body mass index as opposed to obese women.

In a Canadian study published in 2013, researchers evaluated the occurrence of diabetes with the use of six different statins, including Lipitor. Lipitor had the highest increase in risk of diabetes at 22 percent. Some evidence also suggested that the risk of diabetes increased with the size of the dosage.

In 2012, the FDA added a warning about the possible relationship between statins and blood sugar regulation to the labeling for Lipitor. The current FDA-approved labeling notes that increases in HbA1c and fasting serum glucose levels have been reported in conjunction with statin medications like Lipitor. The label does not specifically mention an increased risk of diabetes, however.