Association between atherogenic index of plasma and kidney stones: a case-control study in Chinese adults

Dyslipidemia, characterized by an imbalance of lipids in the blood, has been implicated in the formation of kidney stones (KS). One of the key indicators of dyslipidemia is the atherogenic index of plasma (AIP), which is a marker of lipid ratios that can predict metabolic and cardiovascular diseases. Since both metabolic disturbances and cardiovascular issues are linked to KS, it is crucial to investigate the role of AIP in KS formation. This study aimed to evaluate the association between AIP levels and the KS prevalence among Chinese adults. We conducted a case-control study involving 11,645 KS cases (mean age: 53.25 years, 61.83% male) and 106,112 control participants (mean age: 55.46 years, 50.66% male). The AIP was calculated as the logarithm of the ratio of triglycerides to high-density lipoprotein cholesterol (HDL-C). KS status was determined by ultrasound performed by trained clinicians. The association between AIP levels and the prevalence of KS was examined using multivariable logistic regression, and a restricted cubic spline (RCS) analysis was employed to assess the dose-response relationship. The mean AIP was 0.86 (SD 0.70) in the control group and 0.95 (SD 0.73) in the KS group. Participants with KS had significantly higher AIP values than those without ( P < 0.001). Compared with the lowest AIP quartile, the adjusted odds ratios (ORs) for KS were 1.03 (95% CI: 0.97–1.09), 1.08 (95% CI: 1.02–1.15), and 1.15 (95% CI: 1.08–1.22) across the higher quartiles. In the fully adjusted model, each standard deviation increase in AIP was associated with higher odds of KS (OR: 1.07, 95% CI: 1.04–1.09). RCS analysis confirmed a significant and linear dose-response relationship between AIP levels and KS prevalence ( P -overall < 0.001, P -nonlinear = 0.326). Sensitivity analyses further supported the robustness of these findings. Elevated AIP values were positively associated with higher odds of KS in the Chinese population, suggesting that dyslipidemia, as reflected by AIP, may play a role in KS formation.