Childhood urine mercury excretion: dental amalgam and fish consumption as exposure factors

The authors investigated the effect of amalgam fillings and fish consumption on urine mercury level (UHg), in children aged 4–8 years old inclusive. Using a sample of 60 children, we found that children with amalgam fillings had significantly higher UHg levels than children without amalgams (geometric MEAN=1.412 μg Hg/g versus 0.436 μg Hg/g, respectively, P=0.0001). Subjects with reported higher fish consumption also had significantly higher UHgs (P=0.004). Univariate analyses provide evidence of an association between elevated UHg level and young age (P=0.009), short height (P=0.024), and low weight (P=0.049) in children with amalgam chewing surfaces. We also found a negative correlation between urine mercury and age (−0.378), height (−0.418), and weight (−0.391). A multiple logistic regression model shows that the presence of amalgam fillings leads to increased odds of high UHg in children (OR=47.18), even after adjusting for high fish consumption (OR=8.66) and height (OR=11.36).