Dietary cadmium exposure and fracture incidence among men: A population-based prospective cohort study
Cadmium is an osteotoxic metal present in food. It causes multiple fractures in those highly exposed and is associated with reduced bone mineral density at considerably lower exposures. Little is known about fracture rates following low-level cadmium exposure. We assessed the associations between dietary cadmium exposure and fracture incidence. Within a population-based prospective cohort of 22,173 Swedish men, we estimated individual dietary cadmium exposure using food frequency questionnaire data and levels of cadmium in food. The average intake was 19 µg/day. Hazard ratios (HRs) for any fracture and hip fracture were estimated using Cox's regression. During 10 years of follow-up, we ascertained 2183 cases of any fracture and 374 hip fractures by computerized linkage of the cohort to registry data. Multivariable-adjusted dietary cadmium intake was associated with a statistically significant 19% [HR = 1.19, 95% confidence interval (CI) 1.06-1.34] higher rate of any fracture comparing highest tertile with lowest (p ≤ .01 for trend). Moreover, men in the highest tertile of dietary cadmium and lowest tertile of fruit and vegetable consumption had a 41% higher rate of any fracture compared with contrasting tertiles. Hip fracture rates also were higher in the highest tertile of cadmium intake but only statistically significant among never smokers (HR = 1.70, 95% CI 1.04-2.77). Our results indicate that dietary cadmium exposure at general population levels is associated with an increased rate of fractures among men. This association was independent of smoking and was most pronounced among men with low fruit and vegetable consumption.