Cholesterol, Statins, and Cancer – Just to Confuse You

There was some anxiety when it was reported in 2007 that statin-induced LDL-C (lower low-density lipoprotein cholesterol) levels were linked to an increased risk of cancer. Could statin therapy be responsible? It seemed unlikely, and now their safety has been demonstrated with some certainty in a study reported in the Journal of the American College of Cardiology. This study was conducted by the investigators who first reported a connection between low LDL-C levels and cancer.

The investigators reviewed data from 15 randomize studies of statins that each included over 1,000 person-years of follow-up. Totals of 51,700 patients treated with statins and 45,000 patients given a placebo were followed, on average, for 4½ years. During this time there were 5750 new cases of cancer.

In the statin-treated patients, there were 2.2 new cancers per 1,000 patient-years for every 10 mg/dL decrease in LDL-C. In the placebo-treated patients, the frequency was 1.2 per 1,000 patient-years per 10 mg/dL decrease in LDL-C. Looked at another way, there were 12.6 new cases of cancer per 1,000 patient-years of follow-up, compared with 12.7 per 1,000 for the statin-treated patients – irrespective of the degree or rate of LDL-C lowering. Complicated, but reassuring findings, showing that statins don’t increase the risk of cancer.

Also this month there’s a paper in the Canadian Medical Association Journal describing a study done in Hong Kong . Among Chinese patients with type 2 diabetes, 3,800 who weren’t taking statins were followed over a 5-year period. The 270 cancer cases reported allowed the risk to be assessed in relation to LDL-C levels. The risk of cancer was about 50% greater among those with LDL-C levels below 108 mg/dL or above 147 mg/dL. The intermediate LDL-C levels between 108 and 147 mg/dL had the lowest cancer risk. This study adds a new element to the problem – higher cholesterol levels are also associated with an increased cancer risk! Now it’s up to the scientists to find out why – what’s the mechanism for this U-shaped distribution of risk.