Circulating cadmium concentration and risk of aortic aneurysms: A nested case-control study within the Malmö Diet and Cancer cohort.

BACKGROUND AND AIMS: Diet and smoking expose the general population to cadmium (Cd), which is a toxic metal that accumulates in the arterial wall. In experimental studies, Cd causes reductions in proliferation of smooth muscle cells and cellular synthesis of procollagen. The aim of this study was to examine whether blood Cd levels, a valid measure of Cd exposure, are associated with increased risk of abdominal aortic aneurysm (AAA).

METHODS: All middle-aged men and women enrolled in the Malmö Diet and Cancer study (n = 30 447) were followed from the baseline examination in 1991-1996 through 2009. A total of 297 cases with AAA and two randomly selected control subjects for each case, matched for age and sex, were included. Blood Cd was analysed by inductively coupled plasma mass spectrometry. Diagnoses of AAA, thoracic aortic aneurysm and aortic dissection were obtained from registers.

RESULTS: Increased blood Cd was associated with increased risk of incident AAA after adjustment for smoking and other established risk factors for AAA. The highest tertile of blood Cd concentrations had a rate ratio of 2.5 (95% confidence interval 1.3, 5.0) for incident AAA. Concentration of blood Cd (log transformed) was not associated with AAA in never-smokers (n = 24).

CONCLUSIONS: Blood Cd levels corresponding to the upper tertile of the distribution in the age- and sex-matched control group were associated with a 2.5-fold increase in rate ratio for incident AAA. This relationship was not found in the small group of never-smokers.