Electronic cigarette use and risk of chronic kidney disease: a dose-response analysis with propensity score matching in a nationally representative cohort

The long-term renal effects of electronic cigarette (e-cigarette) use remain poorly understood, despite its global rise as a nicotine delivery system. This study investigates the association between e-cigarette use and chronic kidney disease (CKD), with emphasis on dose-response relationships, subgroup heterogeneity, and adjustment for cigarette smoking. We analyzed data from 872 adults in NHANES (2017-2020). E-cigarette use was categorized by self-reported frequency (non-users, 1-2 days/week, ≥ 3 days/week). CKD was defined as urinary albumin-to-creatinine ratio ≥ 30 mg/g. Weighted multivariable logistic regression models adjusted for age, gender, race, BMI, diabetes, hypertension, and current cigarette smoking. Propensity score matching (PSM, 1:1) balanced baseline covariates, including current smoking. Dose-response trends were assessed via restricted cubic splines (RCS). Among 188 e-cigarette users and 684 non-users, users were significantly younger and had higher serum cotinine. In fully adjusted models (Model 3), e-cigarette use was associated with a 2.50-fold higher odds of CKD (95% CI: 1.80-3.48, P < 0.001). A significant dose-response relationship existed: adjusted ORs for CKD were 1.80 (95% CI: 1.20-2.70) for 1-2 days/week and 2.60 (95% CI: 1.70-4.00) for ≥ 3 days/week use (P-trend = 0.002). This association was significantly stronger in non-diabetics (OR = 2.40, 95% CI: 1.65-3.50) vs. diabetics (P-interaction = 0.032) and in current smokers (OR = 2.35, 95% CI: 1.55-3.56) vs. non-smokers (P-interaction = 0.021). Sensitivity analyses confirmed robustness: PSM yielded OR = 1.89 (95% CI: 1.18-3.01, P = 0.009); excluding dual users yielded OR = 1.98 (95% CI: 1.28-3.06, P = 0.003); and cotinine-based exposure yielded OR = 2.25 (95% CI: 1.43-3.54, P = 0.001). E-cigarette use is independently associated with CKD in a dose-dependent manner, particularly among non-diabetic individuals. Notably, NHANES data limitations include lack of past e-cigarette use or smoking history records, which may introduce residual confounding. These findings highlight vaping as a modifiable risk factor for kidney disease, urging targeted public health interventions.