Association between the atherogenic index of plasma and kidney stones: a nationally representative study

Purpose The atherogenic index of plasma (AIP) is a novel comprehensive lipid index. We aimed to investigate a possible relationship between AIP index and kidney stones in US adults. Methods This cross-sectional study was conducted among adults with complete AIP index and questionnaire records on kidney stones from the National Health and Nutrition Examination Survey (NHANES) spanning from 2007 to 2018. The AIP index served as the exposure variable, defined as the logarithm of the ratio between triglycerides (TG, mmol/L) and high-density lipoprotein cholesterol (HDL-c, mmol/L). Self-reported history of kidney stones was utilized as the outcome variable. The independent relationship between AIP index and the risk of kidney stones was fully assessed. Results A total of 14,833 participants were included in this study, with an average AIP index of -0.07 +/- 0.01. The proportion of kidney stones progressively increased with higher AIP index tertile intervals (7.33% vs. 9.97% vs. 12.57%, P < 0.001). Furthermore, AIP index was found to be independently associated with the risk of kidney stones after adjusting for confounding factors (OR = 1.32, 95% CI 1.08-1.61, P = 0.006). Restricted cubic spline (RCS) analysis confirmed the robustness of our results. There was no significant interaction observed based on subgroup analysis stratified by age, gender, race, body mass index (BMI, kg/m(2)), smokers, diabetes, hypertension, and cardiovascular disease (P for interaction > 0.05). Conclusions The AIP index may be a potential epidemiological tool to quantify the role of dyslipidemia in the risk of kidney stones in US adults.