Dietary fat intake and early age-related lens opacities.

Background: Dietary fat may affect lens cell membrane composition and function, which are related to age-related cataract.

Objective: The objective of the study was to examine the association between long-term dietary fat intake and the prevalence of age-related nuclear, cortical, and posterior subcapsular lens opacities.

Design: Women (n = 440) aged 53-73 y from the Boston area without previously diagnosed cancer, diabetes, or cataract were selected from the Nurses' Health Study cohort. Intakes of total fat and selected fatty acids were calculated as the average of intake data from 5 food-frequency questionnaires collected between 1980 and the study eye examination (1993-1995). Nuclear opacity was defined as grade >/=2.5, cortical opacity as grade >/=1.0, and posterior subcapsular opacity as grade >/=0.5 according to the Lens Opacities Classification System III.

Results: There were significant positive associations between linoleic and linolenic acid intakes and the prevalence of nuclear opacity. The odds ratios for nuclear opacity in women with intakes in the highest quartile and women with intakes in the lowest quartile were 2.2 (95% CI: 1.1, 4.6; P for trend = 0.02) for linoleic acid and 2.2 (95% CI: 1.1, 4.5; P for trend = 0.05) for linolenic acid. There were no significant associations between intakes of any type of fat and either cortical or posterior subscapular opacity.

Conclusions: High intake of the 18-carbon polyunsaturated fatty acids linoleic acid and linolenic acid may increase the risk of age-related nuclear opacity. Further study is needed to clarify the relation between dietary fat and cataract risk.