Study design of the Smart Wellness Housing survey
HBP
The SWH survey was designed with two validation patterns, prepared from short- and long-term viewpoints (Fig. Before and after insulation study [University Hospital Medical InformationNetwork Clinical Trials Registry (UMIN-CTR) Trial No. UMIN000030601]This study was a non-randomized controlled trial with groups categorized according to participants’ choice of whether or not to conduct insulation retrofitting. This intervention included a range of treatments, including heat-insulation work on the outer walls, floor and/or roof; replacing single-glazed with double-glazed windows; and replacing window frames. Thermal insulation performance level after retrofitting was set to meet the S standards (approximately equivalent to a long-life newly built, high-quality house) or A standards (lower than S standards but expected to provide consistently improved performance) of the ‘Act on the Promotion of Dissemination of Long-Lasting Quality Housing’ in Japan [Long-term cohort study (UMIN-CTR Trial No. UMIN000042196)Overview of the Smart Wellness Housing survey in Japan †FY indicates fiscal yearThis cohort study aims to evaluate long-term health effects in relation to differences in thermal insulation level. It is being conducted by a follow-up survey of households for more than 5 years after the completion of insulation retrofitting. Houses with no insulation retrofitting were randomly selected and included as a control group.Participants measured the indoor thermal environment and their home blood pressure (HBP), and kept a diary for 2 weeks, mainly during winter (November–March). They also responded to a questionnaire during the same period. Indoor temperature and relative humidity at 1.0 m above the floor were monitored in the living room, changing room, and bedroom at 10-min intervals by automated monitoring sensors supplied by the investigators and installed by the participants. HBP was also measured twice in the morning and twice in the evening, in accordance with the Japanese guideline [