Effect of minamata disease status and the perception of unfairness on ill health and inequalities in health amongst residents of Shiranui sea communities

Abstract

Minamata disease (MD) is a neurological disorder caused by eating seafood contaminated with methylmercury, fi rst identifi ed in 1956 in Japan. However, reports of ill health related to MD increased sharply following a ruling by the Supreme Court in 2004. We performed logistic regression analyses to examine the relationship between MD specifi c socioeconomic status (MD status) and health inequalities amongst residents of Shiranui sea communities. Data were collected by two-stratifi ed sampling of residents 40-79 years old in 172 postal code areas on the Shiranui sea coast. A questionnaire was distributed to eligible subjects (n = 2100) and collected at a later visit or by mail. Two self-reported health outcomes were examined: MD-related physical symptoms (MDRS) and the 12-item General Health Questionnaire (GHQ-12). We classifi ed the 1546 respondents according to MD status: Early and Recent (received MD compensation before and after the Supreme Court decision, respectively) and Not Yet (yet to receive compensation). Adjusting for confounding factors, Early and Recent was signifi cantly associated with elevated MDRS and GHQ-12 compared with Not Yet. After further adjusting for perception of unfairness, the inequality between Early and Recent was reduced. Efforts to improve the population's health in these areas should consider health effects of MD status and perception of unfairness.

Adverse Effects of Methylmercury: Environmental Health Research Implications

“…Meanwhile, increasing numbers of likely victims were being discovered, in part due to the continued pollution and environmental dissemination. A court decision in 2004 provided recognition and compensation to many additional Minamata disease patients (most of whom had died by that time) ( Ushijima et al 2010 ). However, many thousands were thought to be affected, although not to a degree justifying compensation based on the existing case criteria.…”