Dietary modification ups glaucoma risk in women

Dietary modification (DM) among individuals in the lowest quartile for percentage calories from total fat at baseline is associated with a higher risk of incident primary open-angle glaucoma (POAG) among women, irrespective of age or race, suggests a recent study.

In this secondary analysis of a randomized intervention trial, the investigators tested whether DM contributed to the risk for incident POAG. They linked Medicare claims data to 45,203 women in the Women’s Health Initiative Dietary Modification Trial. Of these, 23,776 participated in the fee-for-service Medicare Part B and had physician claims.

The investigators randomly assigned these women to follow either DM (a low-fat diet, with increased vegetable, fruit, and grain intake; n=9,340) or their usual diet without modification (control group; n=13,877). Analyses were based on an intention-to-treat design, with follow-up until the end of continuous Medicare coverage, death, or the last claims date (31 December 2018).

Dietary data were assessed using a food frequency questionnaire. POAG was defined as the first claim with the International Classification of Diseases, Ninth or Tenth Revision, codes.

The final analysis included 23,717 women (mean age 64.4 years) after excluding those with Medicare-derived glaucoma prior to randomization. Baseline characteristics were similar between the intervention and control groups.

Incident POAG stood at 11.1 per 1,000 woman-years (mean follow-up, 11.6 years; mean DM duration, 5.2 years). DM showed no overall benefit in reducing incident POAG (hazard ratio [HR], 1.04, 95 percent confidence interval [CI], 0.96‒1.12). Race (p=0.08) and age of participants (p=0.24) did not modify this association.

Analysis of baseline nutrient and food intake stratified by quartile groups revealed an increased risk of incident POAG (HR, 1.22, 95 percent CI, 1.05‒1.41; p=0.007 for interaction) in DM participants in the lowest quartile for percentage calories from total fat (33.8 or lower).