The Paradoxical Impact of Socioeconomic Status on Chronic Kidney Disease in Northwestern Iran: Exploring the Interaction ofEthnicity and Social Class

Background Chronic kidney disease (CKD) is a major global public health concern, influenced not only by biological but also by social determinants of health. Socioeconomic status (SES) is a key determinant of CKD, yet its interaction with ethnicity remains underexplored. This study aimed to assess the association between SES and CKD prevalence and to examine ethnic differences in this relationship in a multiethnic population in northwestern Iran. Methods A cross-sectional study was conducted using population base data from the integrated CKD screening within the IraPEN program in Naqadeh County, West Azerbaijan Province, Iran (2018–2019). A total of 7,771 adults aged ≥30 years were analyzed. SES was derived from household asset indicators using polychoric principal component analysis and categorized into tertiles (low, middle, high). Logistic regression models were fitted to estimate adjusted odds ratios (ORs) and 95% confidence intervals (CIs) for CKD, testing interactions between SES and ethnicity. Results The prevalence of CKD was 10.2% (95% CI: 9.5–10.9). Higher SES was associated with a lower likelihood of CKD (middle SES: OR=0.77, 95% CI: 0.62–0.95; high SES: OR=0.59, 95% CI: 0.44–0.79). Women had more than twice the odds of CKD compared to men (OR=2.10, 95% CI: 1.68–2.63). A significant interaction between SES and ethnicity was identified: CKD prevalence decreased with higher SES among Turks but not among Kurds. Model discrimination was excellent (AUC=0.83). Conclusions SES is strongly associated with CKD, but this relationship varies by ethnicity. Context-sensitive, equity-focused interventions are essential to address kidney health disparities in multiethnic settings.