Healthy Buildings 2017 Europe July 2-5, 2017, Lublin, Poland

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1 Healthy Buildings 7 Europe July -5, 7, Lublin, Poland Paper ID 6 ISBN: Effects of the Housing Envelope and Living Behaviour on Body Temperature in the Elderly: A Field Survey Toyohiro Kurabe,*, Tanji Hoshi, Yukie Hayashi, Toshiharu Ikaga Keio University, Yokohama, Japan Tokyo Metropolitan University, Hachioji, Japan * Corresponding kurabe--toyohiro@z7.keio.jp SUMMARY In Japan, 5 % of heatstroke patients transported to hospital by ambulance are elderly. Most cases of heatstroke in the elderly occur at home. Accordingly, this study aimed to determine the relationship between the indoor thermal environment and body temperature as a critical cause of heatstroke in the elderly. A field survey comprising actual measurements and a questionnaire survey was conducted in summer 5. The night-time standard new effective temperature (SET*) was found to be higher in multi-unit houses than detached houses, and was higher on the top floor than middle and lowest floors. Furthermore, the sublingual temperature increased by. C per. C increase in night-time SET*. These results will help proposals aimed at reducing the risk of heat stroke in the elderly. KEYWORDS Heatstroke, indoor thermal environment, air conditioning, sublingual temperature INTRODUCTION In Japan, mainly in downtown Tokyo, the urban heat island is increasing. In Tokyo, the maximum daily temperature is.8 C with an average relative humidity of 7 % in August (JMA, 6), creating a hot and humid climate. Under such conditions, 5 % of heatstroke patients transported to hospital by ambulance are elderly individuals (FDMA, 6). Since most of these cases of heatstroke in the elderly occur at home (NIES, 6), the effect of the indoor thermal environment has attracted attention. A previous study revealed that elderly individuals tend to live in hot and humid indoor thermal environments (Azuma et al. ), largely because of the low thermal insulation performance of the old buildings they often inhabit. Another reason is the lack of measures taken by the elderly to combat heat because of their dislike of the cold, a desire to save energy, and low temperature sensitivity (MOE, 4; Enomoto, 5). Heatstroke is a state in which an individual s body temperature increases dramatically due to a lack of balance between heat production and dissipation in the body (MOE, 4). Accordingly, this study aimed to determine the relationship between indoor thermal environment and body temperature as a critical cause of heatstroke in the elderly.

2 MATERIALS AND METHODS. Participants A field survey comprising actual measurements and a questionnaire survey was conducted in summer 5. The survey area covered Tama New Town, Tokyo, which is home to a number of elderly individuals living in older apartment complexes. A total of 48 participants (7 households) were recruited from adult residents (men and women aged 5 years) through a local day-care facility.. Study protocol Indoor air temperature and relative humidity, as well as sublingual temperature were measured by the participants for approximately weeks, and questionnaires on personal attributes and housing distributed. The personal attribute questions covered individual characteristics such as age, gender, height / weight to calculate body mass index (BMI), and overall health including a history of diseases that could cause heatstroke. The housing questions covered aspects of the indoor thermal environment such as thermal insulation performance (Takayanagi et al. ) and measures implemented to combat the heat.. Indoor air temperature and relative humidity Indoor air temperature and relative humidity were measured at -min intervals at an abovefloor height of. m in the living room and bedroom. Measurements were obtained with a temperature and humidity data logger (RTR-5, T&D Corporation). Indoor thermal environment was evaluated according to the standard new effective temperature (SET*) calculated using air temperature and relative humidity data. The mean radiant temperature (MRT) was assumed to be equal to the air temperature, wind speed was set at. m / s, metabolic rate at. met, and the insulation value of clothing at. clo. The body surface area (BSA, m ) was calculated using the following equation: BSA =.888 W.444 H.66 () where W (in kg) is the weight and H (in m) is the height of the participant (Fujimoto et al. 68)..4 Sublingual temperature The sublingual temperature in the living room was measured by participants at bedtime and on waking using a digital basal thermometer (MC-64L, OMRON Corporation), and a diary completed each morning and night as shown in Table. Table. Diary contents. Night Consumption of water / alcohol / medication Instrument settings of air conditioner / electric fan Window open / closed Bedtime Morning Waking time Initial symptoms of heatstroke Number of trips to the bathroom during the previous night.5 Definitions of night-time SET* and morning sublingual temperature Night-time SET* and morning sublingual temperatures were defined as follows.. Night-time SET*: mean temperature in the bedroom while in bed, the duration of which was determined by the bedtime and waking time listed in the dairy.

3 . Morning sublingual temperature: sublingual temperature measured in the morning..6 Statistical analysis The mean ± standard deviation (SD) was reported for all continuous variables, and compared using a t-test. The magnitude of the association between night-time SET* and morning sublingual temperature was verified using multiple regression analysis. All p-values were two-sided, with p <.5 considered statistically significant. All statistical analyses were performed using SPSS ver.. software. RESULTS. Personal and housing characteristics of the participants A total of 48 participants (7 households) were recruited, and their eligibility assessed according to validation criteria. Four were excluded due to missing temperature data and four due to missing questionnaire data, giving a total of 4 participants ( households). Of the remaining households, 8 (84.8 %) were multi-unit houses. There were a total of five wooden houses (5. %) and 6 non-wooden houses (78.8 %). Most buildings were 4 years old (45.4 %), had single glazing (6.7 %), and an aluminium window frame (8.8 %). Most common measures used to combat the heat were Use an air conditioner followed by Open several doors / windows and third Use an electric fan (Table ). Table. Characteristics of the households included in the final analyses Characteristic Characteristic Living room Bedroom Form, n (%) Window glazing, n (%) Detached house Multi-unit house 5 8 (5.) (84.8) Single Double Structure, n (%) Wooden Reinforced concrete Steel frame Other Building age, n (%) years years years 4 years 4 years (5.) (48.5) (7.) (.) (6.) (7.) (.) (.) (.) (45.5) (6.) Window frame, n (%) Aluminium Aluminium (double) Insulation Old wooden New wooden Measures used to combat the heat, n (%) Use an air conditioner Solar shading Open one door / window Open several doors / windows Use a dehumidifier Use an electric fan (6.7) (7.) (.) (8.8) (.) (.) (.) (.) (6.) (.) (7.) (54.5) (6.7) (.) (6.6) (6.7) (4.) (6.) (8.8) (.) (.) (.) (.) (6.) (78.8) (7.) (5.5) (66.7) (8.) (7.7) Of the 4 participants (mean age ± SD: 74.7 ± 7. years old), 6 (4. %) were men. BMI (mean BMI ± SD:. ±.6 kg/m ) was generally normal (8.5 5.). Twenty patients (5. %) had a history of hypertension (Table ).

4 Table. Baseline characteristics of the 4 participants Characteristic Characteristic Age, mean (SD), y Male, n (%) BMI, mean (SD), kg / m Diseases history, n (%) Diabetes (7.) (4.) (.6) Disease history, n (%) Lung disease Liver disease Kidney disease Endocrine disease Hypertension (5.) Cerebrovascular disease Heart disease Dementia Mental disease Parkinson s disease Heatstroke (.5) (5.) (5.) (.5) (.). Housing characteristics and SET* values In the t-test for night-time SET* (daily, not using air conditioner at night, each households), the night-time SET* of multi-unit housing was significantly higher than that of detached houses (Figure ). Moreover, in a t-test for the night-time SET* of multi-unit housing (daily, not using air conditioner night, each households), the night-time SET* of the top floor was significantly higher than that of the lowest and middle floors (Figure ). Figure. Comparison of night-time SET* Figure. Comparison of night-time SET* between detached and multi-unit housing among floor levels of multi-unit housing. Characteristics and sublingual temperatures of the participants As a preliminary step to study the effects of thermal environment on sublingual temperature, individual differences in sublingual temperature were considered. In the t-test for morning sublingual temperature (daily, each subjects), there were significant differences in age, sex, BMI, liver disease, kidney disease, endocrine disease and dementia (Table 4)..4 Effects of night-time SET* on morning sublingual temperature Morning sublingual temperature was measured in the living room, but this is supposed to be cumulatively affected by night-time thermal environment in the bedroom. There were wide variations in morning sublingual temperatures among the individual participants (Table 4). Multiple regression analysis was therefore used to determine the association between nighttime SET* and morning sublingual temperature considering the effects of individual differences. In the multiple regression model, night-time SET* was significantly associated with morning sublingual temperature, even after adjusting for potential confounders such as age, sex, BMI, and disease history (Table 5).

5 Table 4. Participant characteristics and morning sublingual temperatures Characteristic p-value Characteristic p-value Age, mean (SD), C Liver disease, mean (SD), C 75 years under 6.45 (.) 75 years over 6.5 (.6) <.5 Healthy 6.46 (.8) Under treatment or Cured 6.58 (.) <.5 Sex, mean (SD), C Male Female BMI, mean (SD), C 5 kg / m under 5 kg / m over (.) (.5) <.5 (.8) (.) <.5 Table 5. Multiple regression model Variable R =.8, F =.85, p <. Constant Night-time SET* Age BMI Liver disease Kidney disease, mean (SD), C Healthy Under treatment or Cured Endocrine disease, mean (SD), C Healthy Under treatment or Cured Dementia, mean (SD), C Healthy Under treatment or Cured (.) (.) <. (.) (.5) <.5 (.) (.4) <. Unstandardized coefficient Standardized coefficient t-value p-value B Std. Error β <. <. <. <.5 <. 4 DISCUSSION In this field study of 4 participants ( households), indoor temperature, relative humidity and sublingual temperature data were collected. The differences in night-time SET* were significantly associated with the housing characteristics, with multi-unit housing giving significantly higher values than those of detached houses (p <.). Most of these multi-unit houses were non-wooden, while all of the detached houses were wooden, suggesting that the differences in night-time SET* were affected by the heat capacity of the building structure. Moreover, in the multi-unit houses, the night-time SET* of the top floor was significantly higher than that of the lowest and middle floors (p <.), suggesting that the top floor accumulates heat by solar radiation during the day. The night-time SET* was also significantly associated with an increase in sublingual temperature, even after adjusting for the effects of potential confounders such as age, sex, BMI and disease history. Moreover, age and BMI were associated with an increase in sublingual temperature, probably due to the decrease in muscle mass, including moisture, with age. A history of liver disease was also associated with an increase in sublingual temperature, probably because of deterioration of thermoregulatory function due to weakening of the detoxification effect. In the multiple regression model, a. C increase in night-time SET* was significantly associated with a. C increase in morning sublingual temperature (p <.). A high sublingual temperature increases the risk of heatstroke, suggesting the importance of controlling night-time indoor thermal environment. Based on the above results, residents of multi-unit housing, especially those on the top floor, should pay attention to the warning signs of heatstroke.

6 Despite its findings, this study had limitations. First, we were unable to consider elements other than sublingual temperature as a factor in heatstroke. Analysis of other indexes such as the amount of perspiration is also important; however, are difficult to precisely measure. Second, the overall number of participants, especially those with a history of disease, was low. As a result, the effect of disease history was perhaps inaccurate. An increased number of participants with various characteristics would therefore be beneficial. Third, the participants in this survey were limited to those who didn t develop heatstroke during this period, because those who did were unable to continue with the investigation. The results might therefore have been underestimated. Inclusion of data on heatstroke patients transported to hospital by ambulance would therefore be useful. 5 CONCLUSIONS This study analyzed the relationship between night-time SET* and morning sublingual temperature during a field survey in summer 5. The following were revealed. ) The night-time SET* of multi-unit housing, most of which was non-wooden, was significantly higher than that of detached houses, all of which were wooden (p <.). ) In multi-unit housings, the night-time SET* of the top floor was significantly higher than that of lowest and middle floors (p <.). ) In the multiple regression model, a. C increase in night-time SET* was significantly associated with a. C increase in morning sublingual temperature (p <.). 6 ACKNOWLEDGEMENT The authors gratefully acknowledge the contributions of the staff at AI FARM (NPO) and the study participants. The authors are also grateful to Ms. Maki Ito, Ms. Chika Ohashi, Ms. Eri Honda, Mr. Nakajima for their assistance with data analysis. This study was supported in part by a Grant-in-Aid for Scientific Research (A) (No.648; Principal Investigator: Prof. Toshiharu Ikaga). 7 REFERENCES Azuma M., Sassa N., Tsuzuki K., Kubo H. and Isoda N.. A survey of the thermal environment and a physiological vlalue under the daily life in summer (part) Skin temperature and physical activity of the elderly and the young, Proceedings of the 7 th Symposium on Human-Environment System, Enomoto H., Kubo H., Isoda N. and Yanase T. 5. The Characteristics of the Elderly's Residential Thermal Environment: A Questionnaire Survey of Dwelling in the Summer and Winter of the Kansai Area, Japan society of Home Economics, 46(), -. FDMA. 6. Emergency transport status due to heatstroke in 6 Fujimoto S., Watanabe T., Sakamoto A., Yukawa K. and Morimoto K. 68. Studies on the Physical Surface Area of Japanese: Part 8 Calculation Formulas in Three Stages over All Age, Japanese Journal of Hygiene, (5), MOE. 4. Environmental Health Manual on Heat Strokes in 4. NIES Bulletin Report on Heatstroke Patients Takayanagi E., Ikaga T., Murakami S., Seike T. and Nakano J.. Validation of the effectiveness of residential environment assessment tool for health promotion, Journal of Environmental Engineering, 76(67), -8. JMA. 6. Tables of Climatological Normals (8 )