Ecological correlates of motor neuron disease mortality : a hypothesis concerning an epidemiological association with radon gas and gamma exposure

This study investigates variations in motor neuron disease (MND) mortality rates between the counties of England and Wales from 1981 to 1989, and their relationship with gamma-ray dose rates, indoor radon gas concentrations and enhanced general life expectancy. A strong correlation was confirmed between age-adjusted rates of MND mortality and life expectancy. Weaker, but statistically significant, associations were observed between indoor radon gas concentrations, terrestrial gamma radiation and marginal variations in MND mortality. Life expectancy and radon gas concentrations were positively associated with MND mortality rates whilst gamma radiation was negatively associated. The negative correlation of gamma radiation with MND mortality may be understood with reference to its negative effects on overall population life expectancy. Radon gas concentrations seemingly account for a small elevation in MND mortality, amounting to at most 4% of total deaths. Further research is required to investigate this association.