Hypertension is a Risk Factor for Neovascular Age–Related Macular Degeneration

Abstract

Purpose: : Cardiovascular disease and age–related macular degeneration (AMD) may share common antecedents that involve inflammatory and immune pathways. We evaluated several established risk factors for cardiovascular disease to determine their relationship to risk of neovascular AMD in a retrospective matched case–control study of extremely discordant sibling pairs.

Methods: : As part of an ongoing study to determine genetic and other risk factors for neovascular AMD, we obtained epidemiological data by conducting telephone or in–person standardized interviews with 153 extremely discordant sibpairs (index case with neovascular AMD and an unaffected sibling with normal maculae past the age of diagnosis of the index patient) from 106 families. Disease status was ascertained photographically by two investigators. When necessary (n=6), a home retinal examination was performed. Exposure data were measured up to the age of AMD diagnosis of the index subject or the youngest age of diagnosis in sibships with more than one affected sibling. We assessed the relationship between neovascular AMD and statin use, pack–years of cigarette smoking, alcohol intake, body mass index (BMI), and the presence of hypertension, angina, myocardial infarction, stroke, and hypercholesterolemia. Conditional logistic regression (StataCorp) was performed to identify factors associated with neovascular AMD.

Results: : In univariate models, an increased risk of neovascular AMD was not found to be associated with a history of hypercholesterolemia, obesity or cardiovascular disease nor was a protective effect observed for those taking statins or drinking moderate amounts of alcohol. In multivariable logistic regression, either a history of smoking or hypertension increased the odds of developing neovascular AMD. Smoking at least 10 pack years was associated with an approximate twofold increase in risk (OR: 2.4, 95% CI: 1.3–4.4, p=.005) as was a diagnosis of hypertension which occurred more than 5 years before AMD diagnosis (OR: 2.1, 95% CI: 1.1–3.9, p=.03).

Conclusions: : In this cohort of extremely discordant sibpairs, siblings with neovascular AMD were more likely to be hypertensive or to have smoked than were their unaffected siblings. Associations were not found for other factors such as hypercholesterolemia, statin use and obesity – relatively uncommon findings in our cohort – but may become apparent with analysis of additional sibpairs.

Keywords: age-related macular degeneration • clinical (human) or epidemiologic studies: risk factor assessment