Global burden of intellectual disability resulting from prenatal exposure to methylmercury, 2015

Environ Res. 2019 Mar;170:416-421. doi: 10.1016/j.envres.2018.12.042. Epub 2018 Dec 19.


We describe analyses to estimate the global burden of disease associated with methylmercury (MeHg). An intelligence quotient < 70, indicating intellectual disability (ID), was selected as the critical disease, maternal hair Hg concentration during pregnancy selected as the critical exposure biomarker, and a dose-effect relationship of an 0.18 point IQ reduction per µg/g increase in maternal hair Hg was assumed, based on a meta-analysis. A systematic review was conducted to obtain country-specific data on the distribution of maternal hair Hg concentrations. The country-specific incidence of MeHg-associated ID was calculated, and a random effects model was used to impute the incidence for countries for which no exposure data could be found. The global burden of MeHg-associated ID was quantified in terms of Disability-Adjusted Life Years (DALYs) using the World Health Organization (WHO) Global Health Estimates methodology, and presented by 14 subregions. In 2015, the global total for MeHg-associated cases of ID was 226,655; 210,074 of these cases (93%) were mild cases of ID. The highest rate of ID (6 cases per 100,000 population) was found in the Americas D subregion. The global DALY estimate was 1,963,869. The Western Pacific B subregion contributed the most to this total (696,417), although the Americas D subregion had the greatest rate (54 DALYs per 100,000 population). The burden of disease associated with MeHg is therefore highly subregion-dependent even in areas that are geographically related. The priority given to reducing this burden can therefore be expected to vary considerably by subregion depending on other health needs.

Keywords: Diet; Disability-Adjusted Life Year; Foodborne burden of disease; Intellectual disability; Methylmercury.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Disabled Persons
  • Environmental Exposure / statistics & numerical data*
  • Female
  • Global Health
  • Humans
  • Intellectual Disability / epidemiology*
  • Methylmercury Compounds*
  • Pregnancy
  • Prenatal Exposure Delayed Effects / epidemiology*
  • Quality-Adjusted Life Years


  • Methylmercury Compounds