Analysis of the relationship between proportion of well-insulated homes and excess winter mortality based on statistical information in Japan

This paper describes the relationship between the proportion of well-insulated homes (WIHs) and the excess winter mortality (EWM) index. Results from a regression analysis of a national sample of 47 Japanese prefectures indicate that the proportion of WIHs is negatively correlated with EWM index for both total deaths and CVD. This suggests that residents of WIHs with colder indoor environments are exposed to higher mortality risk in winter compared with residents of well-insulated homes with warmer indoor environments. The results also suggest that the EWM index tends to be higher in prefectures with warmer outdoor temperatures. Therefore, almost everywhere in Japan except its subtropical region, maintaining a warm indoor environment is more important for reducing the risk of winter death than is living where it is warm outdoors.