Association between urinary cadmium levels and prediabetes in the NHANES 2005-2010 population

Abstract

Evidence suggests an association between exposure to cadmium and dysglycemia. To investigate this matter, we examined the relationship between urinary cadmium and prediabetes in the cross sectional National Health and Nutrition Examination Survey (NHANES). NHANES participants for the years 2005 through 2010 aged ≥ 40 years were included in the analysis. Participants with nephropathy, overt diabetes, or missing required data were excluded. To assess the non-linear relationship between cadmium and Prediabetes, non-parametric logistic regression with B spline expansion of urinary cadmium/creatinine ratio was performed. This analysis revealed a complex non-linear association between higher cadmium levels and prediabetes. This relationship persisted, though with varying magnitudes across smoking groups (never smokers, moderate smokers, heavy smokers). In a conventional logistic regression analysis, this relationship was less evident with significantly increased OR for prediabetes was found in the highest quintile of urine cadmium compared to the lowest quintile in the overall population and in moderate smokers. In an age stratified analysis, a significant linear association was found only in the age groups 60-69 and ≥ 70. We conclude that there is a significant non-linear, complex relationship between urinary Cd levels, age, smoking habits and odds of prediabetes.

Keywords: Cadmium; Diabetes mellitus; NHANES; Prediabetes.

Fig. 1

Odds ratios for prediabetes by creatinine-corrected urine cadmium level adjusted for age, race/ethnicity, gender, education, BMI, hypertension, smoking status, packyears, and survey year. Knots are at quintile of urine cadmium distribution (0.183, 0.284, 0.420, 0.654 μg/g). Reference value is set at the 20th percentile of urine cadmium distribution (0.183 μg/g). Odds ratio is displayed as a solid line. The upper and lower limit of the 95% confidence interval is displayed as a dotted line. The histogram illustrates the number of participants at each Cd concentration point. Panel a represents the data from all participants. Panel b represents the data from never smokers. Panels c and d represent data from moderate (0.1–20 pack years and heavy smokers (>20 pack years) irrespective of current smoking status. Panels e, f, g, and h represent the data from former and current smokers, females, and males respectively.