Bone mineral density and age-related maculopathy in older women

To determine whether bone mineral density (BMD) is associated with age-related maculopathy (ARM) risk in older women.

Cross-sectional analysis at Year 10 (1997/98) of the Study of Osteoporotic Fractures (SOF).

Four clinical centers in the United States.

One thousand forty-two randomly sampled SOF participants who attended the Year 10 clinic visit.

ARM status was determined from fundus photographs using a modification of the Wisconsin Age-Related Maculopathy Grading System 6-level severity scale used in the National Health and Nutrition Examination Survey III. Total hip BMD was measured at Year 10 using dual-energy x-ray absorptiometry. Information on potential confounders, including age, reproductive hormone exposures, body mass index, smoking, alcohol consumption, nutrition, education, diabetes mellitus, hypertension, and physical activity, was ascertained with questionnaires.

The prevalence of ARM was 50% (46% had early ARM and 4% had late ARM). After potential confounder adjustment, greater BMD was associated with lower odds of ARM (odds ratio (OR) per 1 standard deviation increase in BMD=0.82, 95% confidence interval (CI)=0.70-0.96). Women in the highest quartile of BMD had lower odds of ARM than those in the lowest quartile (OR=0.63, 95% CI=0.41-0.97) and those in the lowest three quartiles combined (OR=0.66, 95% CI=0.48-0.91).

Higher levels of BMD may be associated with lower risk for ARM. The underlying mechanism is unknown, although BMD may be a marker for lifetime endogenous estrogen exposure. Future studies are needed to replicate these findings and further investigate the nature of the relationship between BMD and ARM.