Neutrophils as mediators of the association between lipid accumulation product and kidney stones, but not for recurrent kidney stones in US adults

Kidney stones (KS) are prevalent and often recur, with obesity, metabolic disorders, and inflammation significantly impacting their pathophysiology. The traditional body mass index (BMI) has limitations, as it cannot effectively differentiate between fat and lean body mass or provide information about fat distribution. In contrast, the lipid accumulation product (LAP), which combines waist circumference and triglyceride levels, serves as a crucial indicator of visceral fat. This study examines the relationship between LAP and KS, including recurrent kidney stones (RKS), using data from the National Health and Nutrition Examination Survey (NHANES). It also investigates whether neutrophils mediate the connection between LAP and KS/RKS, comparing the predictive accuracy of LAP and BMI. Data from 2007 to 2014 covered 9910 KS participants and 880 RKS participants. Weighted logistic regression assessed the LAP-KS/RKS relationship, while mediation analysis explored the role of neutrophils. Receiver Operating Characteristic (ROC) curves evaluated the predictive capabilities of LAP and BMI. Results showed LAP was significantly associated with KS (OR = 1.629; 95% CI 1.296-2.047) and RKS (OR = 1.561; 95% CI 1.145-2.128). Neutrophils partially mediated the LAP-KS relationship (7.6%, p = 0.018), with no effect found for RKS. Moreover, LAP outperformed BMI in diagnostic accuracy. These findings suggest that LAP is an effective marker for assessing KS and RKS, aiding in the early identification of potential patients to reduce the incidence and recurrence of kidney stones.