Cadmium body burden and pregnancy-induced hypertension

Previous studies provided a strong evidence of the association between environmental exposure to cadmium (Cd) and hypertension in the general population. However, the role of Cd in pregnancy-induced hypertension (PIH) remains unclear. A total of 5429 pregnant women was selected from a birth cohort in Wuhan, China to investigate the association between Cd exposure and risk of PIH. Among them, 199 (3.7%) women were diagnosed with PIH. The Cd concentrations in maternal urine collected at delivery were measured by inductively coupled plasma mass spectrometry. Multivariable logistic regression was performed on Cd concentrations as a continuous variable (natural logarithm transformed) or as a categorical variable (tertiles). For about 3-fold increase in urinary Cd concentrations, there was 75% increase in the odds of PIH after adjusting for potential confounders (odds ratio (OR)  = 1.75; 95% confidence interval (CI): 1.45, 2.11). Women in the highest tertile of urinary Cd had 2.2-fold increased OR of PIH, compared with women in the lowest tertile (2.24; 95% CI: 1.47, 3.41). Furthermore, we found a significant interaction between Cd exposure and maternal socioeconomic status on PIH (P for interaction = 0.04). Our findings indicate that higher Cd exposure might increase the risk of PIH, and the association might be modified by socioeconomic status.