Cadmium levels and sources of exposure among Canadian adults.

BACKGROUND Cadmium is a heavy metal found naturally in the environment that has been associated with negative health outcomes. The present study examines levels of blood cadmium (BCd), urinary cadmium (UCd), and the main sources of cadmium exposure among Canadians aged 20 to 79. DATA AND METHODS The data are from cycles 1 (2007 to 2009) and 2 (2009 to 2011) of the Canadian Health Measures Survey (CHMS), including measures of BCd and UCd, markers of smoking status (self-reported and second-hand smoke exposure), and self-reported consumption of foods known to be high in cadmium. The relationship between sources of exposure and cadmium levels was examined descriptively. The magnitude of the contribution of different exposure sources was examined in regression models. RESULTS Age and smoking status were the greatest contributors to BCd and UCd: older people and current smokers had the highest cadmium levels. Dietary exposure, while significant, was a modest contributor overall, but a more important source of cadmium among never-smokers. INTERPRETATION Smoking was the greatest contributor to cadmium levels among Canadians aged 20 to 79. Dietary differences explained a small percentage of variation in cadmium levels.