Environment/Climate Change
The Association Between Temperature and Cardiovascular Death by Housing Type in a Japanese Large City Akihiko Narisada* Akihiko Narisada Tomohiro Umemura Nauta Yamanaka Kohta Suzuki
Background: The relationship between temperature and risk of cardiovascular disease death is nonlinear, with risk increasing both in cold and hot temperatures. In the “HOUSING AND HEALTH GUIDELINES”, the World Health Organization recommends improving the insulation performance of houses and using air conditioners appropriately to maintain appropriate indoor temperatures. However, in Japan, many houses, especially detached houses, still have poor insulation performance. In addition, it is thought that some people, especially those living in apartment buildings, are unable to use air conditioners appropriately for economic reasons. Therefore, it is possible that the risk of cardiovascular death due to temperature differs depending on the type of house. The aim of this study is to examine the relationship between temperature and emergency transport for cardiovascular disease by housing type in a Japanese large city.
Methods: The study included cases in which patients were transported by ambulance from houses due to cardiovascular disease or death between April 2016 and March 2022 in Nagoya city, a city with a population of 2 million located in central Japan. Using a time-stratified case-crossover design, we calculated the risk of transport due to cardiovascular disease using a nonlinear model (distributed lag nonlinear model) with a mean temperature of 15°C as the reference.
Results: There were 31,047 cases (16,926 in detached houses and 14,121 in apartment buildings). Regarding cold, the risk of emergency transport due to cardiovascular disease increased significantly with decreasing temperature in both detached houses (risk of 3℃: RR: 1.12, 95% CI: 1.03-1.21) and apartment buildings (RR: 1.10, 95% CI: 1.01-1.21). On the other hand, regarding heat, no increase in risk was observed in ordinary houses (risk of 30°C : RR: 0.98, 95% CI: 0.85-1.12), but the risk increased significantly in apartment buildings (RR: 1.16, 95% CI: 1.00-1.34).
Conclusions: We examined the relationship between temperature and emergency transport due to cardiovascular disease by housing type in Nagoya City. The risk of cold exposure was elevated in both types, whereas the risk of heat exposure differed by housing type: it was not elevated in detached houses but was elevated in apartment buildings.
