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Introduction: Socioeconomic status and education level have been shown to affect health outcomes. We examined the relationship between poverty level, education level, and 24-hour urine composition in patients with nephrolithiasis.
Materials & Methods: A retrospective review was performed. Poverty level and education level for each zip code were determined from US Census Bureau Data.Multivariate linear regression examined the relationship between poverty level, education level, and 24-hour urine composition. Regression models adjusted for known risk factors for stone disease.
Results: 435 patients were included in the study. Female:male ratio was 173:262 (i.e. 40% female), mean age was 52.5 years (SD 14.4), mean BMI was 28.6 (SD 6.5). On multivariate linear regression, increasing poverty was associated with significant increases in urine calcium (B = 1.51, 95% CI 0.16 to 2.86). There were no other associations between poverty level and any urine constituents or supersaturations. Increasing level of education was associated with significant decreases in urine calcium (B = -1.26, 95% CI -2.42 to - 0.10), supersaturation of calcium oxalate (B = -0.04, 95% CI -0.09 to -0.006), and supersaturation of calcium phosphate (B = -0.013, 95% CI -0.03 tp -0.0002). There were no other associations between education level and any urine constituents or supersaturations.
Conclusions: In this study of stone formers, increasing poverty and lower education level were both associated with increased urine calcium. Further studies are important to elucidate the mechanisms underlying these findings.