The association between cataracts the clouding of the lens of the eye and taking statins the widely used cholesterol-lowering drug class has been studied in the past and results have been inconsistent and controversial. A new observational study conducted by researchers from the University of British Columbia led by Dr. G.B. John Mancini of the Department of Medicine found that statins were associated with an increased risk of developing cataracts.
Researchers used data from the British Columbia Ministry of Health databases from 2000-2007 composed of male and female patients and the IMS LifeLink U.S. database from 2001 to 2011 composed of males ages 40 to 85. They matched 162,501 cases from the British Ministry with 650,000 controls and 45,000 cases from the U.S. database to 450,600 controls. Researchers identified patients who had been on statins for a year before the ophthalmology examination and followed them through diagnosis of cataracts and surgery. They found that patients on any statin drug had a 27 percent increased risk of developing cataracts in the Canadian cohort and a seven percent increased risk of developing cataracts in the U.S. cohort.
According to Dr. Mancini, "Further assessment of the clinical impact of this relationship is recommended, especially given increased statin use for primary prevention of CVD and the importance of acceptable vision in old age where CVD is common. Future studies addressing the possible underlying mechanisms to explain this association are also warranted. However ¦because cataract surgery is both effective and well tolerated, this association should be disclosed but not be considered a deterrent to use of statins when warranted for CV risk reduction."
In an accompanying editorial, Drs. Steven Gryn and Robert A. Hegele of the Department of Medicine at Western University in Ontario point out that while a healthcare provider must always consider the risks versus the benefits of taking a specific medication, in the case of statins, Among patients who are at high CVD risk, like most of those seen by cardiologists...the prevention of CVD, stroke, and their associated morbidity and mortality vastly outweighs the risk of cataracts. Even among lower risk patients, for whom the benefit-risk ratio is less dramatic, most patients would still probably prefer having to undergo earlier non-life-threatening cataract surgery over suffering a major vascular event."
On a related note, the link between statins and new onset diabetes mellitus is also being explored. A recent meta-analysis of 17 trials and over 100,000 patients found a very small association. The meta-analysis also found that the association was dependent on which statin was involved: not all statins were associated with the same degree of glucose intolerance, a condition resulting in higher than normal blood glucose levels and a marker of type 2 diabetes.
However, Dr Francisco Lopez-Jimenez, the director of preventive cardiology at The Mayo Clinic in Rochester, MN, says, We know that in patients with diabetes, statins actually give a pretty strong benefit. We shouldn't be too concerned about increasing the sugar when the benefit is that high.