Economic evaluation of health consequences of prenatal methylmercury exposure in France

Abstract

Background: Evidence of a dose-response relationship between prenatal exposure to methylmercury (MeHg) and neurodevelopmental consequences in terms of IQ reduction, makes it possible to evaluate the economic consequences of MeHg exposures.

Objective: To perform an economic evaluation of annual national benefits of reduction of the prenatal MeHg exposure in France.

Methods: We used data on hair-Hg concentrations in French women of childbearing age (18-45 years) from a national sample of 126 women and from two studies conducted in coastal regions (n = 161and n = 503). A linear dose response function with a slope of 0.465 IQ point reduction per μg/g increase in hair-Hg concentration was used, along with a log transformation of the exposure scale, where a doubling of exposure was associated with a loss of 1.5 IQ points. The costs calculations utilized an updated estimate of €2008 17,363 per IQ point decrement, with three hypothetical exposure cut-off points (hair-Hg of 0.58, 1.0, and 2.5 μg/g).

Results: Because of higher exposure levels of women in coastal communities, the annual economic impacts based on these data were greater than those using the national data, i.e., € 1.62 billion (national), and € 3.02 billion and € 2.51 billion (regional), respectively, with the linear model, and € 5.46 billion (national), and € 9.13 billion and € 8.17 billion (regional), with the log model, for exposures above 0.58 μg/g.

Conclusions: These results emphasize that efforts to reduce MeHg exposures would have high social benefits by preventing the serious and lifelong consequences of neurodevelopmental deficits in children.

Figure 1

Loss of IQ points according to HHg concentrations based on linear and log models. Figure 1 displays the comparison of IQ decrements associated with HHg concentrations based on a linear model in red lines and a logarithm model in blue lines. In the first, estimates of IQ point loss are presented for the three cut–off points 0.58, 1.0 and 2.5 μg/g and for the maximum (i.e. the Percentile P99.5, extreme value excluded) for the three samples. In the log model, IQ point losses are given above 0.58 μg/g. And, we assumed no IQ loss below the three cut-off points.

Figure 2

Estimated annual benefits from MeHg reduction exposure above 0.58 μg/g, in the 2008 children cohort (in €₂₀₀₈ Billion).