Spatial variability of municipality-wise heat and cold mortality in Japan with respect to temperature and economic states

Abstract

A series of statistical analyses are made to find the dependence of heat and cold mortalities on the temperature and economic states of municipalities in Japan, using vital statistics data for 18 years, from 1999 to 2016. A partial correlation analysis for 1,207 municipalities over the country has indicated that heat and cold mortalities are positively and negatively correlated with summer and winter temperatures, respectively, while they are both negatively correlated with annual income and positively correlated with municipality population. These features are essentially common to genders, age groups, and regions, and indicate that heat and cold mortalities depend on both climatic and socioeconomic factors. An additional analysis of 151 wards in Tokyo and 12 other government-designated cities has also shown a correlation between heat/cold mortality and income; in particular, exceptionally high mortality is found in some wards which have areas with poor living conditions.