Association between blood lead level and gout: the United States National Health Nutrition and Examination Survey 2007-2014

Abstract

Introduction: Lead is a heavy metal without a biological role in humans. It is hypothesised to increase the risk of gout by increasing serum urate level and reducing renal function. High blood lead level (BLL) is associated with an increased risk of gout. Whether this association still holds at lower BLLs is uncertain. Therefore, we aimed to evaluate the association between BLL and gout in the US population. Methods: Adult participants with blood lead measurements in the US National Health Nutrition and Examination Survey 2007-2014 were included in this analysis. Gout was defined as a self-reported diagnosis of gout. Results were analysed using SPSS (Windows version 22.0; IBM Corp, Armonk [NY], US). Logistic regression with sample weight adjustment was used to study the association between BLL and gout. Odds ratios (ORs) and 95% confidence intervals (95% CIs) were estimated using logistic regression with sample weight adjustment. Results: A total of 18 837 participants were included in this analysis. The prevalence of gout increased with BLL. Every doubling in the BLL was associated with gout (OR=1.66, 95% CI=1.50-1.84). This association remained significant after adjustment for estimated glomerular filtration rate, family poverty-to-income ratio, hypertension, diabetes, thiazide diuretics prescription, and body mass index (OR=1.43 [95% CI=1.24-1.66]). Using quintile 1, BLL <0.89 μg/dL, as reference, BLL ≥1.49 μg/dL was associated with increased gout risk (BLL 1.49-<2.21 μg/dL vs quintile 1: OR=2.48 [95% CI=1.55-3.97]; BLL ≥2.21 μg/dL vs quintile 1: OR=3.21 [95% CI=1.98-5.21]). Conclusion: Blood lead level, even at low levels, is associated with gout. The risk of gout is increased when the blood lead level is ≥1.49 μg/dL. Therefore, measures should be taken to minimise the environmental exposure to lead.