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  • A Strict Low-Fat Diet May Raise Glaucoma Risk

    By Lynda Seminara
    Selected by Russell N. Van Gelder, MD, PhD
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    Journal Highlights

    Ophthalmology, June 2023

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    Using data from the Women’s Health Initiative (WHI) Dietary Modification Trial, Mehta et al. explored glaucoma risk among women who followed a low-fat diet that was high in fruits, vegetables, and grains. They found that incident glaucoma was more common when fat consumption was very low.

    For this research, prospective WHI data for women ≥50 years of age were linked to Medicare Part B claims. Par­ticipants were assigned randomly to ad­here to their usual diet (control group) or follow the dietary modification (20% of energy from fat, ≥5 servings of fruits/vegetables, and ≥6 servings of grains per day). The diagnosis of primary open-angle glaucoma (POAG) was determined by the first medical claim that included relevant ICD-9 or ICD-10 codes. Participants completed a food-frequency questionnaire, and their responses were analyzed. Cox pro­portional hazards models were used to calculate hazard ratios (HRs) and 95% confidence intervals (CIs) for POAG risk. Subgroup analyses by fat intake level also were conducted.

    After excluding patients with glaucoma present before randomization, 23,217 partici­pants remained (13,877 in the control arm, 9,340 in the intervention arm). Baseline characteristics were similar for the two groups. The over­all incidence of POAG was 11.1 per 1,000 woman-years (mean follow-up time, 11.6 ± 7.4 years; mean duration of dietary modification, 5.2 ± 3.2 years). The data analysis did not show lower POAG risk in the modi­fied-diet group (HR, 1.04; 95% CI, 0.96-1.12). Neither race nor age altered the findings. The quartile subgroup analysis by nutrient intake showed that the group with the lowest daily consumption of fat (≤33.8%) had the highest risk of POAG (HR, 1.22; 95% CI, 1.05-1.41; p = .007 for interaction).

    To reduce glaucoma risk, the investi­gators concluded that “a careful design of future lifestyle and diet modifica­tions is needed,” including a healthy balance of fat intake. (Also see related commentary by Emily Y. Chew, MD, in the same issue.)

    The original article can be found here.