Prospective study of plasma homocysteine level and risk of age-related macular degeneration in women.

Prospective data to examine the association of homocysteine with age-related macular degeneration (AMD) are limited. We examined the prospective relation of plasma homocysteine level and AMD in a large cohort of apparently healthy women. We evaluated the relationship between baseline levels of plasma homocysteine and incident AMD among 27,479 female health professionals aged 40 years or older. Main outcome measures were total AMD, defined as self-report documented by medical record evidence of an initial diagnosis after randomization, and visually significant AMD, defined as confirmed incident AMD with visual acuity 20/30 or worse attributable to this condition. During an average 10 years of follow-up, a total of 452 cases of AMD, including 182 cases of visually significant AMD, were documented. Women in the highest versus lowest quartile of plasma homocysteine had modestly, but statistically non-significant, increased risks of total AMD (hazard ratio, HR, 1.24, 95% confidence interval, CI, 0.95-1.63; p for trend 0.07) and visually significant AMD (HR 1.41, 95% CI 0.92-2.17; p for trend 0.052) in age- and treatment-adjusted analyses. These prospective data from a large cohort of apparently healthy women do not support a strong role for homocysteine in AMD occurrence.