Dietary macronutrient intake and five-year incident cataract: the blue mountains eye study

To investigate the relationships between dietary macronutrient intake at baseline and the five-year incidence of the three main types of cataract in older people.

Population-based cohort study.

An urban community near Sydney, Australia.

The Blue Mountains Eye Study (BMES) examined 3,654 predominantly Caucasian participants aged 49+ years during 1992 to 1994, and then 2,335 survivors (71.5%) after five years. Of these 2,335 subjects, 1988 (85%) completed a Willett-derived food frequency questionnaire (FFQ) at baseline.

A 145-item FFQ was used to assess nutrient intakes and lens photography was used to assess the presence of cataract at both time points.

Incidence of cortical, nuclear, and posterior subcapsular (PSC) cataract was assessed via lens photographic grading following the Wisconsin cataract grading method.

After adjusting for multiple known cataract risk factors, higher dietary intakes of omega-3 polyunsaturated fatty acids (n-3 PUFA) were associated with a reduced incidence of nuclear cataract. The odds ratio (OR) for subjects in the highest quintile of intake compared to those in the lowest quintile was 0.58 (95% confidence interval [CI] 0.35 to 0.97), P(trend) = .027. Similarly, for PSC cataract, higher dietary intakes of protein were protective (OR 0.28; 95% CI 0.10 to 0.76), P(trend) = .015. Dietary macronutrient intake was not associated with incident cortical cataract.

Higher dietary intakes of n-3 PUFA may decrease the five-year risk of nuclear cataract, whereas higher dietary intakes of protein may decrease risk for PSC cataract.