RAR Emerges as Potential Indicator of Cataract Risk in Population Study

A large NHANES analysis published in Advances in Ophthalmology Practice and Research reveals that elevated red blood cell distribution width-to-albumin ratio (RAR)—a marker of systemic inflammation and nutritional status—is significantly associated with higher cataract risk. The relationship persisted after full adjustment and across most demographic and clinical subgroups, suggesting RAR may serve as an accessible biomarker to support earlier identification, risk stratification and preventive strategies for cataract development. Photo: Gleb Sukhovolskiy, OD. Click image to enlarge. Although age is a non-modifiable risk factor associated with cataract development, several modifiable risk factors, such as diabetes, ultraviolet radiation exposure and smoking, have all been key targets for prevention and control. Systemic chronic inflammation has also been implicated in the pathogenesis, potentially accelerating lens protein denaturation and aggregation. Among these, red blood cell distribution width-to-albumin ratio (RAR) is an emerging composite biomarker calculated as the ratio of red blood cell distribution width to serum albumin concentration. Under conditions of chronic inflammation, oxidative stress and nutritional deficiency, RAR levels increase, suggesting a possible association with cataract development. Since this theory was previously unexplored in the literature, a group of researchers recently published a study in Advances in Ophthalmology Practice and Research that showed a significant positive link between elevated RAR and cataract risk. The cross-sectional study used data from the US National Health and Nutrition Examination Survey (NHANES) from 1999 to 2008. RAR was calculated using red blood cell distribution width and serum albumin measurements collected at mobile examination centers, and self-reported history of cataract surgery served as a proxy for cataract diagnosis. Covariates included sociodemographic factors, lifestyle variables and comorbidities. Researchers employed multivariable logistic regression and propensity score matching. The analytical cohort comprised 26,397 participants with a mean age of 49.5 years (49.3% male and 50.7% female). Cataract was present in 2,295 participants (8.7%). According to the results, cataract patients exhibited significantly higher RAR values (3.22) compared to non-cataract participants (3.06). After adjustment for all covariates, a positive association between RAR and cataract was observed, both when RAR was treated as a continuous variable (odds ratio, OR: 1.41) and when analyzed categorically by quartiles. Participants in the highest RAR quartile had significantly increased cataract risk relative to the lowest quartile (OR: 1.57). Subgroup analysis revealed no significant interaction effects across covariates (age, gender, race/ethnicity, education level, marital status, economic status, BMI, smoking/alcohol, hypertension, hyperlipidemia and diabetes), with the RAR-cataract association remaining statistically significant in most subgroups. The authors wrote in their paper, “RAR is an emerging composite biomarker integrating two independent biological indicators reflecting systemic inflammation and nutrition-related status, providing a more comprehensive assessment of homeostatic imbalance.” They continued, “Published literature indicates that RAR is significantly associated with incidence and prognosis of various diseases, including cardiovascular events, diabetic comorbidities, cancer, sepsis, depression and intracerebral hemorrhage. Within the field of ophthalmic diseases, RAR was also related to the incidence of age-related macular degeneration and diabetic retinopathy.”The researchers proposed that RAR could serve as a practical tool for routine cataract monitoring, given its cost-effectiveness and ease of measurement. They noted, “For patients with chronic inflammatory conditions, in addition to managing comorbidities and improving lifestyle, future research should focus on evaluating the potential effects of anti-inflammatory therapies and albumin supplementation for cataract prevention.”Several limitations of this study warrant acknowledgement, including this being the first cross-sectional study on the topic and the use of self-reported surgery history, which may not accurately reflect the prevalence of cataract. Researchers were also limited in their exploration of cataract severity and its association with RAR.They concluded, “RAR represents a promising novel biomarker for cataract risk assessment and early prevention, highlighting the critical role of systemic inflammation and nutritional deficiency in cataract pathogenesis.”Click here for the journal source. Zhang R, Shentu X. Association between red blood cell distribution width to albumin ratio (RAR) and cataract risk: A cross-sectional study from NHANES 1999–2008. Advances in Ophthalmology Practice and Research. December 1, 2025. [Epub ahead of print.] This article was developed by the editorial staff in conjunction with experts in the field. In the process, AI may have been among the editorial tools used to meet the goals of human editors, who approved all content.