Cadmium and mercury levels in Saudi women and its possible relationship with hypertension

The association between elevated blood pressure and blood cadmium and mercury levels was examined (2001-2002) in 185 Saudi women previously selected for a case-control study of lead and hypertension risk. Blood pressure was measured twice according to the World Health Organization recommendations. Cadmium and mercury were determined with graphite furnace and hydride system-atomic absorption spectrometry, respectively. Mean blood cadmium concentrations were 0.874 +/- 0.995 mu g/L in hypertensive and 0.785 +/- 0.665 mu g/L in controls. While blood mercury concentrations for hypertensives and controls were 3.506 +/- 3.617 mu g/L and 3.687 +/- 3.186 mu g/L, respectively. Participants were classified according to the median of blood cadmium and mercury levels. After adjustment for potentially confounding variables, the final logistic regression analyses revealed that women with blood cadmium >= 0.627 mu g/L were 3.934 times were more likely to be hypertensive than those with blood cadmium levels < 0.627 mu g/L, although this was marginally significant (p = 0.098). This was likely the result of the small number of subjects, resulting in the weak power to detect a strong significant difference between hypertensives and control cases. On the other hand, the final regression model showed no association between hypertension and mercury. However, this finding should not be conclusive because of the inappropriate choice of the biomarker indicator. Nevertheless, our study supports the hypothesis that exposure to cadmium might increase the risk of hypertension.