Did you hear the one about statin drugs and an increased risk for diabetes? No we’re not talking about a joke; we’re talking about a study that came out not long ago which indicated an association between statin drugs (used to reduce cholesterol levels) and an increased risk for type 2 diabetes. Naturally studies that raise concerns about very common pharmaceutical drugs make for eye-catching headlines and easy clickbait. But it’s important to separate the wheat from the chaff and make sense of whether sensationalist headlines on the TV news have any relation to what the studies actually show. 

When diet exercise and targeted nutritional supplementation are unable to reduce someone’s risk for a cardiovascular event statin drugs may have a place in reducing related risk factors. But like all compounds that significantly alter a complex biochemical process in the body statins bring many unintended consequences. While an increased risk of elevated blood sugars—which can potentially lead to developing type 2 diabetes—is small it is significant enough that the U.S. Food and Drug Administration (FDA) and the highly respected Mayo Clinic both list elevated blood glucose and increased risk for type 2 diabetes as potential effects of statin drug use. The FDA also provides a note acknowledging reports of elevated hemoglobin A1c (HbA1c) a longer-term measurement of blood sugar in patients taking statin drugs.

A recent study added more fuel to the fire when the results indicated an increase in new diabetes diagnoses among men ages 45-73 who were taking statin drugs. Compared to subjects not taking statins those receiving statin therapy had a 46% increased risk for type 2 diabetes. For certain types of statins the risk was dose-dependent meaning the higher the dose of the statin the greater the increased risk for type 2 diabetes. Compared to study subjects not being treated with statins subjects who were on statins had a 24% reduction in insulin sensitivity and a 12% reduction in insulin secretion.

Let’s look a little more closely at the study. Out of a total of 8749 subjects who were studied for nearly six years 625 were newly diagnosed with diabetes. (Meaning they were not diabetic at the beginning of the study.) However compared to subjects who remained healthy throughout the follow-up period those who developed type 2 diabetes were older more obese less physically active had lower HDL levels higher fasting blood glucose and HbA1c and higher triglycerides. So these subjects had multiple risk factors for developing type 2 diabetes and metabolic syndrome—a cluster of markers that indicate carbohydrate intolerance—regardless of whether they were taking a statin or not. This doesn’t negate a potential role for statins in contributing even further to the risk for diabetes but it’s important to note that these subjects were already at a higher risk.

During the 6-year follow-up period 11.2% of study participants treated with statins were diagnosed with diabetes compared with just 5.8% of those not taking statins. Since that is quite a difference is there a plausible biochemical mechanism that can explain why statin drugs would bring with them a decrease in insulin secretion and increased risk for diabetes? In fact there is. The purpose of statin drugs is to reduce the endogenous production of cholesterol—that is cholesterol the body makes internally. The way they do this is by blocking the effects of a particular enzyme called HMG CoA reductase. However this enzyme’s action occurs very early in a long complex pathway at the very end of which is the production of cholesterol. But when the enzyme is inhibited cholesterol isn’t the only thing whose production is reduced. Production of everything else along the pathway is also reduced and some of these other compounds are required for proper functioning of the pancreatic beta-cells which secrete insulin. This is what accounts for the potential of statin drugs to interfere with proper insulin secretion a downstream effect of which would be elevated blood sugar. 

Whether you are taking pharmaceutical drugs or not the best way to support overall wellness and maintain healthy blood sugar levels is to remain physically active get sufficient sleep and eat a nutrient-dense diet composed of whole unrefined foods. Overweight individuals may benefit from reducing carbohydrate intake while individuals who are more active and are already at a healthy body weight may tolerate higher amounts of carbohydrates.

Sources

1. Cederberg H et al. Increased risk of diabetes with statin treatment is associated with impaired insulin sensitivity and insulin secretion: a 6 year follow-up study of the METSIM cohort. Diabetologia. 2015 May;58(5):1109-17.
2. Volek JS Feinman RD. Carbohydrate restriction improves the features of Metabolic Syndrome. Metabolic Syndrome may be defined by the response to carbohydrate restriction. Nutr Metab (Lond). 2005 Nov 16;2:31.
3. Kowluru A. Regulatory roles for small G proteins in the pancreatic beta-cell: lessons from models of impaired insulin secretion. Am J Physiol Endocrinol Metab. 2003 Oct;285(4):E669-84.
4. Kowluru A. Protein prenylation in glucose-induced insulin secretion from the pancreatic islet beta cell: a perspective. J Cell Mol Med. 2008 Jan-Feb;12(1):164-73.