Association of the content of zinc, cobalt and molybdenum in urine with diabetes mellitus in community-dwelling elderly individuals in Yinchuan, China

Objective To investigate the content levels of zinc, cobalt, and molybdenum in urine of the elderly individuals at communities of Yinchuan, China, and to explore the association of the contents of zinc, cobalt, and molybdenum in urine with the prevalence of diabetes mellitus.

Methods Multilevel sampling method was applied to collect the subjects and a questionnaire survey was used to collect general demographic information, and physical examination was performed to measure the indicators including blood pressure, blood lipids, and liver function. Meanwhile, the mass concentration of zinc, cobalt and molybdenum in the urine were determined by inductively coupled plasma mass spectrometry, with urinary creatinine correction. The subjects were divided into case group and control group according to the presence or absence of diabetes mellitus to perform a descriptive analysis of general demographic information. The data were analyzed by t-test, the non-parametric test, and the chi-square test. The mass concentrations of Zn, Co, and Mo were grouped by quartile, and the Logistic regression analysis and the stratified analysis were used to investigate the association of the contents of zinc, cobalt, and molybdenum in urine with the prevalence of diabetes mellitus and the intensity of such association.

Results A total of 1 998 community elderly individuals were investigated, among whom there were 227 patients with diabetes mellitus (11.36%). There were no significant differences in age, sex, smoking and drinking between the two groups, but the proportion of patients with hypertension, hyperlipidemia and heart disease in the diabetic group was higher than that in the control group, and the mass concentrations of cobalt, zinc and molybdenum in the urine of the diabetic group were higher than those of the control group, and the differences were statistically significant. Compared with the Q₁ group, the Q₄ group in terms of the mass concentrations of urinary zinc and cobalt had odds ratio (OR)and 95% confidential intervals (CI)of 4.10 (2.56, 6.58)and 1.61 (1.06, 2.43), respectively, for the risk of diabetes mellitus, and the Q₃ group in terms of urinary molybdenum had OR of 1.53 (1.02, 2.30)for the risk of diabetes mellitus. For male individuals, compared with the Q₁ group, Q₂, Q₃ and Q₄ groups in terms of urinary zinc had OR(95%CI) of 2.67 (1.04, 6.86), 4.57 (1.86, 11.23), and 5.17 (2.10, 12.75), respectively, for the risk of diabetes mellitus; as for female individuals, Q₃ and Q₄ groups in terms of urinary zinc had OR(95%CI) of 2.36 (1.30, 4.31)and 3.91 (2.22, 6.87), respectively, for the risk of diabetes mellitus, and the Q₄ group in terms of urinary molybdenum had an OR(95%CI) of 2.03 (1.14, 3.63)for the risk of diabetes mellitus.

Conclusion There is a positive correlation between urinary zinc, cobalt, and molybdenum mass concentrations and the risk of diabetes mellitus in the elderly at the community, and this correlation is more obvious in the female population.