Urinary cadmium, osteopenia, and osteoporosis in the US population

Abstract

The association between cadmium and osteoporosis in a multiethnic population is unclear. We found that urinary cadmium is consistently associated with osteopenia and osteoporosis in the Third National Health and Nutrition Examination Survey, regardless of age, sex, race, and smoking status. Cadmium exposure may be an independent risk factor for osteoporosis. Our purpose was to test whether cadmium exposure is associated with a higher prevalence of osteopenia and osteoporosis in the general US population and selected subgroups. We used multinomial logistic regression to analyze data on 10,978 subjects (aged 30-90) from the Third National Health and Nutrition Examination Survey. We studied the association of urinary cadmium levels (adjusted for urinary creatinine) and the prevalence of osteopenia and osteoporosis as defined by the World Health Organization. After adjustment for age, sex, ethnicity, body mass index, calcium intake, and physical inactivity, odds ratios (ORs) for osteopenia and osteoporosis increased dose dependently with two urinary cadmium levels (in micrograms of urinary cadmium per grams of urinary creatinine: level I, 1.00-1.99 mcg/g; level II, > or =2.00 mcg/g). Osteopenia results were as follows: level I OR, 1.49 (95% confidence interval [CI], 1.24-1.80); level II OR, 2.05 (95% CI, 1.52-2.78). Osteoporosis results were as follows: level I OR, 1.78 (95% CI, 1.26-2.52); level II OR, 3.80 (95% CI, 2.36-6.14). The association was consistent in all age, sex, race, and smoking status subgroups. Cadmium exposure may be a potential risk factor for osteopenia and osteoporosis in the general US population.