Associations between urine cobalt and prevalence of kidney stones in American s aged ≥ 20 years old

To determine whether urine cobalt is associated with the prevalence of kidney stones. We conducted a cross-sectional study of participants (≥ 20 years) involved in the National Health and Nutrition Examination Survey (NHANES) between 2007 and 2018. Urine cobalt level was divided into four groups: 0.02–0.22, 0.22–0.36, 0.36–0.58 and 0.58–37.40 ug/L. The independent correlation between urine cobalt and prevalence of kidney stones was determined by logistic regression analyses. Totally 10,744 participants aged over 20 years without pregnancy were eligible. Among them, 1,041 participants reported as ever having developed kidney stones. Patients with kidney stones developed significantly higher urine cobalt than the non-stone participants. The kidney stone patients were more likely to have smoking ≥ 100 cigarettes in life, hypertension, diabetes, cancer, and heavy activity. Multivariate logistic regression indicated a significantly positive relationship between urine cobalt level and occurrence of kidney stones (OR 1.059, 95%CI 1.018–1.102). Moreover, the outcome remained unchanged after some sophisticated factors were adjusted (OR 1.048, 95%CI 1.005–1.093), and the incidence of kidney stones rose with the increasing urine cobalt level [OR (95%CI) = 0.22–0.36 ug/L: 1.166 (0.955–1.422); 0.36–0.58 ug/L: 1.348 (1.108–1.640); 0.58–37.40 ug/L: 1.683 (1.382–2.044)]. Higher urine cobalt concentration is significantly related to an increased risk of kidney stones. However, more high-quality prospective studies are needed to elucidate the causal correlation between cobalt level and kidney stones.