Kang et al. evaluated the association of cholesterol levels and statin use with risk for developing primary open-angle glaucoma (POAG), using data from three population-based cohorts (the Nurses' Health Study, the Nurses' Health Study 2, and the Health Professionals' Follow-up Study).1 These studies had followed nurses and other health professionals for four years or more and employed health questionnaires for data gathering. In addition, reported incident cases of glaucoma - and more specifically for POAG - were verified by expert review of the clinical data from their eye care professionals, including slitlamp examination, visual field testing, maximal intraocular pressure, and optic nerve information.
There were 136,782 participants among the cohorts and 886 incident cases of POAG during the study periods. Self-report of high cholesterol was associated with 17% increased risk for POAG (RR, 1.17 [95% CI, 1.00-1.37]). It was also found that for every increase of 20 mg/ dL of total serum cholesterol, there was a 7% increase in risk for POAG (RR, 1.07 [95% CI, 1.02-1.11]). In terms of statins, participants with any history of statin use had a 15% lower risk for POAG (RR, 0.85 [95% CI, 0.73-0.99]). When duration of statin use was evaluated, there was statistically significantly lower risk (21% lower risk) for POAG at five years or greater duration (RR, 0.79 [95% CI, 0.65-0.97]), when compared to no use of statin drugs.
The authors have found within the same population cohorts that lower cholesterol and statin use are associated with lower risk for incident glaucoma. These results are overall consistent with prior studies. Strengths of the current study include a large population sample, incidence data from a prospective observational study design, and expert review of clinical data related to glaucoma diagnosis. Weaknesses include non-population-based subjects, a predominantly white cohort of subjects, and potential selection bias for getting more timely eye examinations among those who have high cholesterol and/or are being treated for high cholesterol. What would be interesting to study in the future is whether use of statin drugs can be helpful for glaucoma prevention or treatment even among those within the normal range of cholesterol levels.