Dietary Inflammatory Potential and the Risk of Incident Kidney Failure in the Women’s Health Initiative

Background: Diet affects inflammation and kidney health, but few studies have investigated dietary inflammatory potential in CKD progression, particularly in women. We aim to examine this association in the Women’s Health Initiative (WHI). Methods: We conducted a non-concurrent prospective cohort study among WHI participants enrolled in the clinical trials and observational study (1993-1998) without baseline CKD and with available dietary intake assessments, Medicare data, and creatinine measurements at enrollment. The inflammatory potential of diets was assessed using the dietary inflammatory index (DII ® ), an acultural tool that quantifies diets from anti-inflammatory to pro-inflammatory. Scores were categorized into quartiles, with Q1 ( reference group ) and Q4 indicating the least and most inflammatory diets, respectively. Incident kidney failure (CKD stage G5, ESKD, or transplantation) was identified using diagnosis codes in Medicare claims from enrollment through 12/31/2019. We performed multivariable Cox proportional hazards regression and modeled death as a competing risk to determine the risk of incident kidney failure. Results: Among the 17,334 women included in our study, the baseline mean age was 64.9 years (standard deviation 7.1); 33.5% self-identified as Black, 8.8% as Hispanic, 38% had hypertension, and 6.8% had diabetes mellitus. Baseline mean estimated glomerular filtration rate (eGFR) was 87.2 ml/min/1.73m 2 . Over a mean follow-up of 11.2 years, 1852 women (10.7%) developed kidney failure. Compared to Q1, women with dietary patterns in Q4 had a 18% higher risk (95% confidence interval 1.03-1.37; p - trend=0.01) of developing kidney failure after adjusting for age, race/ethnicity, education, region, comorbidities, medications, smoking, energy intake, physical activity, eGFR, and body mass index. Competing risk models yielded similar results. Conclusions: A pro-inflammatory diet (e.g., enriched in processed foods, refined sugars, and red meat) was associated with incident kidney failure in postmenopausal women without baseline CKD. Clinical trials are needed to assess the impact of an anti-inflammatory dietary pattern on CKD risk and progression.