Disability Weights for Chronic Mercury Intoxication Resulting from Gold Mining Activities: Results from an Online Pairwise Comparisons Survey

Abstract

In artisanal small-scale gold mining, mercury is used for gold-extraction, putting miners and nearby residents at risk of chronic metallic mercury vapor intoxication (CMMVI). Burden of disease (BoD) analyses allow the estimation of the public health relevance of CMMVI, but until now there have been no specific CMMVI disability weights (DWs). The objective is to derive DWs for moderate and severe CMMVI. Disease-specific and generic health state descriptions of 18 diseases were used in a pairwise comparison survey. Mercury and BoD experts were invited to participate in an online survey. Data were analyzed using probit regression. Local regression was used to make the DWs comparable to the Global Burden of Disease (GBD) study. Alternative survey (visual analogue scale) and data analyses approaches (linear interpolation) were evaluated in scenario analyses. A total of 105 participants completed the questionnaire. DWs for moderate and severe CMMVI were 0.368 (0.261–0.484) and 0.588 (0.193–0.907), respectively. Scenario analyses resulted in higher mean values. The results are limited by the sample size, group of interviewees, questionnaire extent, and lack of generally accepted health state descriptions. DWs were derived to improve the data basis of mercury-related BoD estimates, providing useful information for policy-making. Integration of the results into the GBD DWs enhances comparability.

The Lancet Commission on pollution and health

“…111 Two particularly common types of contaminated sites are used lead-acid battery recycling sites, where lead is the principal pollutant, and artisanal and small-scale gold mining sites, where the principal pollutant is elemental mercury (which is used to extract gold from ore). We used the methods of Ericson and colleagues 111 to assess the burden of disease associated with lead-acid battery recycling sites, and the methods and data of Steckling and colleagues 112,113 to assess the burden of disease associated with gold mining sites 114-116 These methods are described in detail in the appendix (pp [16][17][18][19].…”

“…202 Two types of contaminated sites that have begun to be studied in detail are used lead-acid battery recycling sites and artisanal and small-scale gold mining sites (table 2). 112,113,203 Lead poisoning from informal battery recycling is seen in low-income countries in all regions of the world. 187,[204][205][206] Artisanal and small-scale gold mining takes place worldwide, but is most highly concentrated in Africa.…”

Global Burden of Disease of Mercury Used in Artisanal Small-Scale Gold Mining

“…14,15,17,29 Recently, the tool was reevaluated by Doering et al 30 to develop a set of essential indicators to simplify data collection. For the current analysis, the condensed version 20 of the detailed disease description of moderate CMMVI 21 was used to define the health outcome of interest. The health outcome was assessed applying the diagnostic tool called "essential indicators" 30 but limited to the single information on elemental mercury in urine.…”

“…Thus, Steckling et al estimated DWs for moderate and severe CMMVI to calculate YLDs as a result of the use of mercury in ASGM. 20 The validly of these DWs is limited because only a small sample of respondents (n ¼ 105) was used to evaluate the severity of a selected set of different diseases. Moreover, comparability with GBD is limited because similar but not exactly the same methods were used to derive DWs.…”

“…Recently, DWs for chronic mercury intoxication as a result of metallic mercury vapor were derived to improve the input data for DALY quantifications. 20 The DWs were based on detailed case descriptions of moderate and severe chronic metallic mercury vapor intoxication (CMMVI), 21 which is assumed to be the main health outcome resulting from exposure to mercury in ASGM.…”