Plant-based diets and the risk of age-related cataract: a case-control study

Purpose Cataract, or lens opacification, is a major public health burden accounting for more than half of all blindness worldwide. Plant-based dietary indices provide a unique approach to investigating a modifiable risk for age-related cataracts (ARC). The purpose of this study was to investigate the association between plant-based diet indices and risk of ARC. Design/methodology/approach This case-control study was conducted on 97 patients with newly diagnosed ARC and 198 healthy people (as a control group) in Iran. Convenience sampling and a food frequency questionnaire were used. Three plant-based dietary indices were used based on the health promoting qualities of food items, the overall plant-based diet index (PDI), healthful plant-based diet index (H-PDI) and unhealthful plant-based diet index (U-PDI) which comprised refined carbohydrates and highly processed foods. The plant-based dietary indices were used to investigate relationships with risk of ARC. Findings After adjusting for potential covariates, no significant association between a higher adherence to O-PDI and risk of ARC. As well, a higher adherence to H-PDI was inversely associated with the risk of ARC (OR = 0.35,95%CI:0.16–0.78). In contrast, there was a significant positive association between a higher adherence to U-PDI and the risk of ARC (OR = 3.67,95%CI:1.66 – 8.15). Originality/value The findings of this study have underscored the potential impact of the quality of plant-based food selections on the likelihood of developing ARC. Therefore, adopting a plant-based diet that is rich in nutrient-dense plant-based foods while being low in unhealthy options may have the potential to reduce the risk of ARC.