Association between Dietary Inflammatory Index and kidney stones in US adults: Data from the NHANES 2007-2016

Objective: We evaluate the association between the Dietary Inflammatory Index (DII) and kidney stones. Design: We performed a cross-sectional analysis using data from National Health and Nutrition Examination Survey. Dietary intake information was assessed using first 24-HR dietary recall interviews, and the Kidney Conditions was presented by questionnaire. The primary outcome was to investigate the association between DII and incidence of kidney stones, and the secondary outcome was to assess the association between DII and nephrolithiasis recurrence. Setting: The National Health and Nutrition Examination Survey (NHANES), 2007-2016. Participants: The study included 25984 NHANES participants, whose data on DII and kidney stones were available, of whom 2439 reported a history of kidney stones. Results: For the primary outcome, after fully multivariate adjustment, DII score is positively associated with the risk of kidney stones (OR = 1.07; 95% CI: [1.04–1.10]). Then, compared Q4 with Q1, a significant 38% increased likelihood of nephrolithiasis was observed. (OR=1.38; 95% CI: [1.19–1.60]). For the secondary outcome, the multivariate regression analysis showed that DII score is positively correlated with nephrolithiasis recurrence (OR=1.07; 95% CI: [1.00–1.15]). The results noted that higher DII scores (Q3 and Q4) are positively associated with a significant 48% and 61% increased risk of nephrolithiasis recurrence compared with the reference after fully multivariate adjustment. (OR=1.48; 95% CI: [1.07–2.05]; OR=1.61; 95% CI: [1.12–2.31]). Conclusions: Our findings revealed that increased intake of pro-inflammatory diet, as a higher DII score, is correlated with increased odds of kidney stones incidence and recurrence.