Prospective study of plasma homocysteine, its dietary determinants, and risk of age-related macular degeneration in men

ABSTRACT

Purpose: Cross-sectional and case–control studies generally support a direct association between elevated plasma homocysteine and age-related macular degeneration (AMD), but data from prospective studies are limited. We examined the prospective relation of plasma homocysteine level, its dietary determinants, and risk of AMD in a large cohort of apparently healthy male physicians.

Methods: During a mean follow-up of 11.2 years, we identified 146 incident cases of visually significant AMD (responsible for a reduction of visual acuity to 20/30 or worse), and 146 controls matched for age, smoking status, and time of blood draw. We measured concentration of homocysteine in blood samples collected at baseline using an enzymatic assay. and we assessed dietary intake of B vitamins and related compounds betaine and choline with a food frequency questionnaire administered at baseline.

Results: AMD was not associated with plasma level of homocysteine; the multivariable-adjusted odds ratio (OR) of AMD comparing the highest and lowest quartile of homocysteine was 1.09 (95% confidence interval [95% CI]: 0.52–2.31; p for trend = 0.99). However, AMD was inversely associated with quartile of intake of total folate (OR: 0.55; 95% CI: 0.24–1.23; p for trend = 0.08), vitamin B₆ from food (OR: 0.39; 95% CI: 0.17–0.88; p for trend = 0.01), and betaine (OR: 0.53; 95% CI: 0.22–1.27; p for trend = 0.048).

Conclusions: These prospective data from a cohort of apparently healthy men do not support a major role for homocysteine in AMD occurrence, but do suggest a possible beneficial role for higher intake of several nutrients involved in homocysteine metabolism.

KEYWORDS:

• Homocysteine
• diet
• age-related macular degeneration
• case–control

Funding

Supported by grants CA 097193 (which included funding from the National Eye Institute and the National Institute on Aging), CA 34944, CA 40360, HL 26490, HL 34595, and EY 18820 from the National Institutes of Health (Bethesda, MD), an investigator-initiated grant from BASF Corporation (Florham Park, NJ), and a gift from ScienceBased Health (Houston, TX). Study agents and packaging were provided by BASF Corporation and Pfizer (formerly Wyeth, American Home Products, and Lederle) (New York, NY), and study packaging was provided by DSM Nutritional Products, Inc. (formerly Roche Vitamins) (Parsippany, NJ).

Disclosure statement

None of the authors have any proprietary interests or conflicts of interest related to this submission.

This submission has not been published anywhere previously nor is it being simultaneously considered for any other publication.

Additional information

Funding

Supported by grants CA 097193 (which included funding from the National Eye Institute and the National Institute on Aging), CA 34944, CA 40360, HL 26490, HL 34595, and EY 18820 from the National Institutes of Health (Bethesda, MD), an investigator-initiated grant from BASF Corporation (Florham Park, NJ), and a gift from ScienceBased Health. Study agents and packaging were provided by BASF Corporation and Pfizer (formerly Wyeth, American Home Products, and Lederle) (New York, NY), and study packaging was provided by DSM Nutritional Products, Inc. (formerly Roche Vitamins) (Parsippany, NJ).