Misc

90% of Japanese homes do not meet the WHO housing and health guidelines for a minimum room temperature of 18℃ in winter. Promotion of warm homes by improving thermal insulation performance during new construction and renovation is expected to have the effect of preventing chronic disease, reducing frail risk and long-term care. This article introduces medical evidence on housing and health based on the nationwide intervention survey for 2,000-household / 4,000-residrnts and other large-scale studies done by authors.

This article introduces the current situation of LCA for buildings. The research and development on LCA method of buildings started in 1990 as an activity of the Architectural Institute of Japan, and it became LCA guideline of buildings. By using of this guideline, the cost effectiveness evaluation tool to mitigate climate change was developed and applied by national and local government, and widely used by many private companies. As well as simplified LCA method was developed and introduced into the comprehensive assessment system for built environment efficiency named "CASBEE: Comprehensive Assessment System for Built Environment Efficiency" for all kind of buildings such as detached houses and large-scale commercial buildings. Furthermore, the human health impact assessment methods associated with indoor environment including indoor air pollution are conducted.

Current countermeasures for preventing hypertension emphasize only improvements to lifestyle. Recently, improving life environment has attracted attention, in parallel with publication of the WHO Housing and health guidelines. We quantitatively evaluated the relationship between housing thermal environment and blood pressure (BP) in a real-world setting. We conducted a nationwide, prospective intervention study-the Smart Wellness Housing survey-in Japan, as a non-randomized controlled trial. The intervention was the retrofitting of thermal insulation in houses. Participant recruitment was done by construction companies in all 47 prefectures of Japan. Measurements of home BP and indoor temperature at 1.0 m above the floor in the living room, changing room, and bedroom were taken for 2 weeks before and after the intervention each winter (November-March) of FY 2014-2019. As of July 2022, over 2500 households and 5000 participants were registered in the database. We found that (1) about 90% of Japanese lived in cold homes (minimum indoor temperature <18 °C), (2) indoor temperature was non-linearly associated with home BP, (3) morning systolic BP (SBP) was more sensitive than evening SBP to changes in indoor temperature, (4) SBP was influenced by indoor temperature change particularly in older participants and women, (5) unstable indoor temperature was associated with large BP variability, and (6) insulation retrofitting intervention significantly reduced home BP, especially in hypertensive patients. We proposed that the BP reduction effect of the life-environment is comparable to that achievable by lifestyle.

This paper describes the outline of heatstroke risk evaluation model for aged residents based on surveys done by the Heatstroke Surveillance Committee of Japanese Association for Acute Medicine and field measurements of indoor air temperature, humidity and so on. To reduce heatstroke of aged residents, promotion of thermal insulation, sun-shading, cross ventilation, air-condition of houses and living behavior of residents are needed.