Published papers

The residential environment clearly affects health. For example, a previous study has established relationships between specific environmental factors and the health status of residents in detached houses. However, studies focused on apartment buildings are still insufficient. Therefore, in this study, a large nationwide questionnaire survey of residents of apartments was conducted. The residential environment was subjectively evaluated using a Japanese Comprehensive Assessment System for Built Environment Efficiency (CASBEE) tool: the CASBEE Health Checklist. The results showed that residents living in apartments who score higher on the checklist tend to have a lower prevalence of various diseases, indicating that residential environment may be an important determinant of health. Furthermore, the odds ratios for residents living in apartment buildings were lower for diabetes mellitus, hypertensive diseases, heart diseases, cerebrovascular diseases, chronic lower respiratory diseases, and inflammatory polyarthropathies compared with residents living in detached houses. These findings support the general link between the residential environment and residents' health and suggest that housing typology is an important factor.

The WHO Housing and health guidelines recommend a minimum indoor temperature of 18°C to prevent cold-related diseases. In Japan, indoor temperatures appear lower than in Euro-American countries because of low insulation standards and use of partial intermittent heating. This study investigated the actual status of indoor temperatures in Japan and the common characteristics of residents who live in cold homes. We conducted a nationwide real-world survey on indoor temperature for 2 weeks in winter. Cross-sectional analyses involving 2190 houses showed that average living room, changing room, and bedroom temperatures were 16.8°C, 13.0°C, and 12.8°C, respectively. Comparison of average living room temperature between prefectures revealed a maximum difference of 6.7°C (Hokkaido: 19.8°C, Kagawa: 13.1°C). Compared to the high-income group, the odds ratio for living room temperature falling below 18°C was 1.38 (95% CI: 1.04-1.84) and 2.07 (95% CI: 1.28-3.33) for the middle- and low-income groups. The odds ratio was 1.96 (95% CI: 1.19-3.22) for single-person households, compared to households living with housemates. Furthermore, lower room temperature was correlated with local heating device use and a larger amount of clothes. These results will be useful in the development of prevention strategies for residents who live in cold homes.

BACKGROUND: Customarily, bedrooms in Japan are left unheated. Although several studies have reported that the use of a heating system has positive outcomes on respiratory infection and asthma, the preventive effect of heating systems against infectious diseases in children is not well known. METHODS: We conducted a cohort study using two questionnaire surveys, one before the winter season in November, 2018 and the second after winter in March, 2019. Participants were 155 children who did not use a heating system in the bedroom and 156 children who did. RESULTS: Having a heated bedroom with a heating system was associated with decreased odds for the frequency of cold (≥3 times) (adjust odds ratio [AOR] 0.35; 95% confidence interval [CI], 0.19-0.65), duration of fever (≥3 days) (AOR 0.38; 95% CI, 0.22-0.66), duration of medicine for a cold (≥3 days) (AOR 0.91; 95% CI, 0.87-0.95), hospital visit due to cold (≥3 days) (AOR 0.54; 95% CI, 0.31-0.94), absence from school or nursery (≥3 days) (AOR 0.43; 95% CI, 0.27-0.70), influenza infection (AOR 0.43; 95% CI, 0.26-0.71), and gastroenteritis (AOR 0.39; 95% CI, 0.21-0.72). Influenza vaccination reduced the odds of influenza infection (AOR 0.36; 95% CI, 0.22-0.59) and absence from school or nursery (≥3 days) (AOR 0.62; 95% CI, 0.39-0.99). CONCLUSION: This study implies that the heating of bedrooms may have a preventive effect against infections among children. Broader dissemination of this knowledge in Japan will require cultural change through public health awareness.

This study examined the housing effect on quality of life among Japanese people. In the current cross-sectional study, we analyzed the 1-year of data (November 2015-March 2016) with 2533 participants. We used the Short Form-8 questionnaire, an 8-item instrument that measures general aspects of health-related QOL. Comprehensive Assessment System for Built Environment Efficiency housing checklist which was developed by Ministry of Land, Infrastructure, Transport and Tourism was used to assess the housing aspects. This checklist has six health elements including thermal comfort, acoustic environment, lighting environment, hygiene, safety, and security for 8 distinctive rooms/places of home. Multilevel analysis was done to identify the relationship between the perceived level of housing problem and PCS and MCS by clustering by sex. Compared to those who always felt unsafe at home due to interior design problem, participants who never felt unsafe showed an average of 10.51 (95% CI = 7.69-13.34, p < 0.0001) and 5.78 (95% CI = 2.90-8.65, p < 0.0001) higher physical and mental component score (better quality of life), respectively. Those who never had thermal, acoustic, lighting, hygiene, and security problems of housing also exhibited significantly better quality of life compared to participants who felt these problems.

A cold ambient temperature in the house may be associated with risk of respiratory infection. In this study, we aimed to determine if there is a significant association between a perception of a cold bedroom and the presence of upper respiratory infection symptoms in order to inform efforts to reduce the incidence of upper respiratory infections in the study population. For this study, subjects were purposely selected from employees and their spouses of a single company in Kyushu, Japan. The study was conducted from December 2018 to March 2019. Each subject was asked to complete a self-administered questionnaire and which best classified how they felt at bedtime: never, sometimes or always. Each subject was also asked whether they had upper respiratory tract infection symptoms, whether they took over-the-counter medication or saw a physician for their symptoms. Between-group differences were examined for significance using the Chi square test. Logistic regression analysis was used to evaluate the potential association between the level of perceived coldness and the likelihood of having an upper respiratory tract infection and its consequences. A total of 1196 subjects were included in the study, 64% male (826 employees (89% male) and 370 spouses (8% male)). The mean age of study subjects was 44 (+/- 12) years. Of the total subjects, 44%, 44% and 12% never/rarely felt cold at bedtime, sometimes felt cold at bedtime and often/always felt cold at bedtime, respectively. Of the total subjects, 52% had upper respiratory tract infection symptoms. When compared with subjects who never/rarely felt cold, subjects who always/often felt cold had significantly greater odds of having upper respiratory tract infection symptoms (adjusted odds ratio (adjusted OR) = 2.56; 95% confidence interval (CI): 1.33-4.91; p = 0.005), having taken over-the-counter drugs for upper respiratory tract infection symptoms (adjusted OR = 1.90; 95% CI: 1.95-2.91; p = 0.003), having taken sick leave for an upper respiratory tract infection (adjusted OR = 3.54; 95% CI: 1.63-7.69; p = 0.001) and having visited a doctor for upper respiratory tract infection symptoms (adjusted OR = 3.22; 95% CI: 1.18-8.80; p = 0.022). In our study population, feeling cold in the bedroom at nighttime was significantly associated with having upper respiratory tract infection symptoms, visiting a doctor and taking sick leave. A change in the room temperature at nighttime should be considered for those who feel cold at nighttime. Further studies are needed to determine if changing the temperature of the bedroom so the person does not feel cold at nighttime will result in fewer episodes of upper respiratory tract infections or not.

Energy consumption in the Chinese residential sector is increasing quickly. In this study, we developed a Micro-model to forecast residential CO2 emissions. The model outputs support decision making for appropriate CO2 emission reduction goals. First, for Chinese urban residential buildings, we developed a CO2 emissions forecast model for 2050 taking into account lifestyle changes and Global Warming countermeasures. Second, we used the model to estimate the CO2 reduction potential of both residential and electrical countermeasures. Compared to the business as usual (BaU) scenario, implementation of residential countermeasures achieved 38%, 24% and 23% emissions reductions for Beijing, Shanghai and Hong Kong respectively. After combining them with the implementation of electrical countermeasures the reduction rates rose to 60%. We also compared the countermeasures to see which could bring the greatest emissions reduction. For Beijing, improvement of insulation was most efficient. For Shanghai and Hong Kong, COP increase of hot water supply appears to be the most efficient countermeasure. Through this study we were able to model global warming countermeasures for the Chinese residential sector, and found that reducing CO2 emissions by 60% from BaU is an achievable goal.

AIM: Issuance of the WHO Housing and health guidelines has paralleled growing interest in the housing environment. Despite accumulating evidence of an association between outdoor temperature and serum cholesterol, indoor temperature has not been well investigated. This study examined the association between indoor temperature and serum cholesterol. METHODS: We collected valid health checkup data of 2004 participants (1333 households), measured the indoor temperature for 2 weeks in winter, and divided participants according to whether they lived in a warm (average bedroom temperature ≥ 18℃), slightly cold (12-18℃) or cold house (＜12˚C). The relationship between bedroom temperature and serum cholesterol was analyzed using multivariate logistic regression models, adjusting for demographics, lifestyle habits and the season in which the health checkup was conducted, with a random effect of climate areas in Japan. RESULTS: The sample sizes for warm, slightly cold, and cold houses were 206, 940, and 858, respectively. Compared to those in warm houses, the odds ratio of total cholesterol exceeding 220 mg/dL was 1.83 (95%CI: 1.23-2.71, p=0.003) for participants in slightly cold houses and 1.87 (95%CI: 1.25-2.80, p=0.002) in cold houses. Similarly, the odds ratio of LDL/non-HDL cholesterol exceeding the standard range was 1.49 (p=0.056)/1.67 (p=0.035) for those in slightly cold houses and 1.64 (p=0.020)/1.77 (p=0.021) in cold houses. HDL cholesterol and triglycerides were not significantly associated with bedroom temperature. CONCLUSION: Besides lifestyle modification, improving indoor thermal environment through strategies such as installing high thermal insulation and appropriate use of heating devices may contribute to better serum cholesterol condition.

As hubs of intellectual activity, offices are expected to promote work efficiency and support worker health. Many studies have analyzed the relationship of the office environment with work efficiency and the health of workers. However, few studies have compared the effects of various elements of the office environment on these outcomes and their economic benefits. To address this limitation, this study investigated the impact of various environmental elements on both work efficiency and health, and analyzed the economic benefits of optimizing these elements in office spaces. The impacts of each element of the office environment on work efficiency and worker health were analyzed for 1644 workers in 29 office buildings in Tokyo, Japan. Economic benefits were estimated by comparing perceived work efficiency to an ideal office and presenteeism to the absence of health-related barriers. The results showed that the office interior and furnishings provided the largest estimated economic benefits, followed by overall building sanitation and HVAC airflow. These elements produced economic benefits associated with high perceived work efficiency. The largest estimated economic benefits associated with low presenteeism was from desk lighting, which was the fourth largest economic benefit overall. The results suggest that healthy offices require not only improvements but also the removal of negative elements. These findings are expected to contribute to the realization of comfortable, healthy offices.

目的 「住まい」は人が最も長く曝露を受ける場である。厚生労働省は地域包括ケアシステムの取り組みの中で,土台としての高齢者のプライバシーと尊厳が十分に守られた住環境,すなわち騒音やカビ等の「住まい(以下「物理環境」)」,住居状況や社会的支援等の関わりの「住まい方(以下「社会環境」)」の重要性を基本的要素として掲げている。本研究は,災害公営住宅への移転も進んだ2018年度の被災高齢者を対象に,現在の住居形態と「物理環境」「社会環境」の関連を明らかにすることを目的とした。方法 2011年度に岩手県沿岸部で実施した大規模コホート研究(RIAS Study)に参加した65歳以上のうち,2018年度調査票の回答者3,856人を対象とした。現在の住居形態に関する設問から住居形態は以下の分類とした:"震災前と同じ(同所再建含)","仮設・みなし仮設","災害公営住宅","新所新築","その他"。「物理環境」については,国土交通省が行うスマートウェルネス住宅等推進調査事業における住宅健康チェックリストを用い,「社会環境」については,RIAS調査票より,独居,ソーシャルネットワーク,ソーシャルキャピタルについて評価した。"震災前と同じ(同所再建含)"と比較した他の住居形態と,「物理環境」「社会環境」の各項目の関連を,多変量ロジスティック回帰分析,重回帰分析より検討した。結果 最終的な解析対象は3,856人(男性39.1%,平均年齢74.6歳)であった。住居形態と「物理環境」の関連では,震災前と同じ群と比較し,新所新築,災害公営住宅,その他の群で住まいの健康度が高く,仮設・みなし仮設群の健康度が低かった。一方,「社会環境」との関連では,震災前と同じ群と比較し,災害公営住宅群で独居者が有意に多く,災害公営住宅,新所新築群でソーシャルキャピタルが有意に低かった。また,ソーシャルネットワークでは,震災前と同じ群と比較し,災害公営住宅群で有意に低く,サポートの内訳では,災害公営住宅群では家族からのサポート,新所新築群では友人からのサポートが有意に低かった。結論 高齢者においては,特に既存コミュニティの有無にかかわらず新たな土地でソーシャルキャピタルやソーシャルネットワークを築くことが難しいことが示された。地域に出るきっかけづくりを含む,長期的な高齢者支援のあり方について早急な取り組みが求められる。(著者抄録)

The simplified method of LCCO2 assessment and the environmental labeling for Comprehensive Assessment System for Built Environment Efficiency（CASBEE）are outlined as the practical application of LCA for buildings in this report. At the same time, the definition and the evaluation method of “Zero Energy Building” which is the latest environmental trend in the architectural design field are described.

Urbanization and change of lifestyle deprive children of their chance to participate in community activities. This paper analyses the structural relationship of factors of children's participation and their health factors focusing on community safety and parents' attitude toward community activities. A questionnaire was conducted to elementary and junior high school students and their parents in Kume Area, Matsuyama City where residents are earnest over various activities for community safety. In conclusion, it is suggested that children's participation has significant relationship with their physical and mental health and that they feel sense of community if they feel safe in the community.

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.

The research 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 the public building department, the Ministry of Land, Infrastructure and Transport as a operation tool for Green government design guideline in 1998. A similar evaluation tool that suits each climate of various regions was developed and applied by local governments and private companies. As well as LCA, the comprehensive assessment system for building environmental efficiency named “CASBEE” was developed supported by the Ministry of Land, Infrastructure and Transport. Since 2004, more than 1300 buildings have been assessed and ranked by national government, local governments and private companies using CASBEE tool, and in 2007, CASBEE was revised to contain simplified LCA method limited to LCCO2 calculation for all kind of buildings such as detached houses and large-scale commercial buildings. This paper describes current situation on these projects of which the author has taken charge.

目的:断熱改修が冬季の住宅内の座位行動と身体活動に及ぼす影響を検討した。方法:断熱改修に意欲的な成人を募集し,冬季2週間のベースライン調査(改修前)と,その1～4年後の同時期に追跡調査(改修後)を行った。住宅内の座位時間と低強度以上の身体活動量(light-to-vigorous physical activity;LVPA)は,加速度計と外出記録から評価した。断熱改修を行った介入群と断念した対照群に対象者を分け,住宅内の座位時間とLVPAの変化との関連を線形混合モデルで検討した。また,脱衣所室温変化量[低下(-1℃未満),変化なし(-1℃以上+1℃未満),上昇小(+1℃以上+5℃未満),上昇大(+5℃以上)]を説明変数に加えた解析も実施した。結果:1,751名(介入群1,640名,対照群111名)を解析対象とした。脱衣所室温は介入群で有意に上昇したが,群間で調査期間のずれが生じたことなどにより,対照群の室温も外気温の上昇に伴い上昇していた。多変量解析の結果,断熱改修と住宅内の座位時間・LVPAの変化に有意な関連は認められなかった。ただし,脱衣所室温変化量は有意に関連していた。室温が変化しなかった場合に比べて,5℃以上改善した場合は,座位時間が減少し,LVPAは増加したが,室温が低下した場合には,座位時間が増加し,LVPAは減少した。結論:断熱改修は住宅内の座位時間とLVPAの変化に関連していなかった。ただし,脱衣所等の室温改善は,住宅内の座位行動を抑制し,LVPAを増加させる可能性が示唆された。今後も検証が必要である。(著者抄録)

Objective: We aimed to examine the effects of insulation retrofitting on sedentary behavior time (SBT) and light-to-vigorous physical activity (LVPA) at home in adults during winter. Methods: Adults intending to retrofit their insulation participated in a 14-day baseline survey in winter and a follow-up survey 1–4 years after retrofitting. Participants were classified into an intervention (insulation retrofitting) or a control (non-insulation retrofitting) group. SBT and LVPA changes were calculated using an accelerometer and questionnaires. A multilevel model was fitted to estimate the effects of insulation retrofitting on these changes. As a secondary analysis, the change in dressing room temperature (Td) from baseline was added as an independent variable in the model, categorized as a decrease in Td (<-1.0°C), no change in Td (-1.0°C to +0.9°C), a small increase in Td (+1.0°C to +4.9°C), and a large increase in Td (≥+5.0°C). Results: Of the 1751 participants, 1640 were in the intervention group. Both groups experienced an increase in Td. The intervention group experienced a slight increase in outside temperature, whereas the control group experienced a significant increase in outside temperature. Insulation retrofitting was not significantly associated with SBT and LVPA at home; however, the change in Td was significantly associated with SBT and LVPA. Compared to no change in Td, the large increase in Td was associated with a decrease in SBT and an increase in LVPA. In contrast, the decrease in Td was associated with an increase in SBT and a decrease in LVPA. Conclusion: Insulation retrofitting was not associated with changes in SBT and LVPA in adults during winter. However, improving room temperature, including Td, could potentially decrease SBT and increase LVPA in adults. Further research is needed to confirm the effect of insulation retrofitting on SBT and LVPA.

記事種別: 会議・学会報告・シンポジウム

目的 本研究の目的は,我が国の冬期における戸建て住宅各室の室温と外気温の実態と共にその関連性について,国土交通省の定める省エネ地域区分別に明確にすることである。方法 本研究の対象者は,日本全国に居住している3,781人である。調査は2014年度冬季より,国土交通省の支援を得て全国的に実施されている,SWH(Smart Wellness Housing)事業の一環として5年間実施した。各部屋別(居間・寝室・脱衣所)に測定された冬期二週間の床上1m室温と床近傍室温,それに気象庁が測定した外気温の実態とともに,その関連について共分散構造分析を用いて解析した。これらの関連は,同時分析により全国の省エネ地域区分別に解析した。分析ソフトは,SPSS22.0とAMOS22.0を用いた。結果 冬季における住居内床近傍室温は床上1m室温よりも低く,時間帯でみると床近傍ないし室温共に朝が低い温度を示した。部屋別室温較差は,居間と脱衣所間で大きかった。室温を地域別にみると,省エネ地域2の室温が最も高く,省エネ地域4の室温が最も低いことが示された。冬期の外気温は各室温よりも床近傍室温と強い関連がみられた。結論 我が国の住宅床近傍室温は,床上1m室温よりも低いことと,居間と脱衣所とでは大きな温度較差がみられた。省エネ地域区分4の住宅床近傍室温と床上1m室温が最も低いことが示された。室温が外気温から影響される度合いは,省エネ地域7を除き地域番号とともに大きくなることが示された。(著者抄録)