Even as new guidelines recommend prescribing Lipitor more widely, several studies — and hundreds of lawsuits — have alleged the drug may make some patients more likely to develop type-2 diabetes.

And a new study has found that Lipitor may also increase the risk of one type of cancer.

A new study on Lipitor, published in the peer-reviewed journal Clinical Endocrinology, found that patients who suffered thyroid cancer were more likely to have used Lipitor than their peers. The study was a case-control study, a type of medical study in which researchers locate a group of patients with one outcome, in this case thyroid cancer, and compare them to a similar group of people without cancer and see what makes them different.

In this case, researchers found 500 people with thyroid cancer and 2,500 people without cancer and gave them all a detailed medical workup. It was found that patients with thyroid cancer were 40 percent more likely to have used Lipitor or other statins. Curiously, the effect was most pronounced in women, a pattern seen with other alleged Lipitor side effects.

Lipitor is the flagship of a class of drugs called statins, which are already controversial. In November 2013, the American Heart Association and the American College of Cardiology issued new guidelines for using statins like Lipitor to prevent complications from high cholesterol.

These guidelines were met with some criticism in the medical community, as they could translate to millions of Americans with new Lipitor prescriptions. Some physicians have questioned these guidelines on the grounds that the protection from heart disease may not outweigh the burden of side effects in such a large group. Theoretically, if millions of people are taking a drug, even rare side effects could start showing up regularly, burdening many with serious health problems.

Lipitor and Diabetes

Lipitor is already at the center of mass legal action over the allegation that the drug can cause type-2 diabetes. Several studies have found that older women taking Lipitor have an increased risk of developing type-2 diabetes compared to their peers.

This has led to thousands of Lipitor lawsuits, which have been coordinated into a single Lipitor MDL. MDL, short for multidistrict litigation, is a type of group legal action in which similar lawsuits are coordinated in order to streamline the legal process.

Since Lipitor lawsuits within the larger Lipitor MDL often hinge on similar evidence and testimony, and make similar claims, MDLs can allow the legal system to avoid duplicating efforts and save time and money for all parties involved. The Lipitor diabetes lawsuits in the Lipitor MDL typically allege that drug makers were aware of the risk of type-2 diabetes allegedly linked to Lipitor, but didn’t do enough to protect the public from these risks.

The Lipitor MDL is In re: Lipitor (Atorvastatin Calcium) Marketing, Sales Practices and Products Liability Litigation (No. II), MDL No. 2502, in the U.S. District Court for South Carolina.