Association between sleep and residential environments in the summertime in Japan.
OBJECTIVE
We aimed to identify the effect of environmental factors on sleep in the summertime in Japan.


METHODS
A self-reported questionnaire survey was conducted in Japan. Age of participants ranged from 20 to 70 years.


RESULTS
The mean Pittsburgh Sleep Quality Index (PSQI) score was 4.9 (±2.7), and 123 (35.0%) participants had scores of >5. According to the results of multivariate logistic regression analysis, the adjusted odds ratio (aOR) for PSQI scores of >5 without installation of air conditioner was 1.8 (95% confidence interval [CI], 1.0-3.3; P<.05), use of a light bulb was 3.7 (95% CI, 1.1-12.6; P<.05), and noise was 2.1 (95% CI, 1.1-4.1; P<.05) after controlling for several confounding variables. Difficulty initiating sleep (DIS) was associated with installation of an air conditioner (1 [reference] to 3 [aOR, 2.5 {95% CI, 1.2-5.1}] and 4 [aOR, 2.8 {95% CI, 1.1-7.1}]) and noise (1 [reference] to 3 [aOR, 2.4 {95% CI, 1.0-5.9}] and 4 [aOR, 8.8 {95% CI, 3.1-25.0}]). Difficulty maintaining sleep (DMS) was associated with installation of a fan (1 [reference] to 2 [aOR, 0.4 {95% CI, 0.2-0.8}] and noise (1 [reference] to 3 [aOR, 2.3 {95% CI, 1.0-5.3}]) after controlling for several confounding variables.


CONCLUSIONS
Our finding using analysis of the association between residential environments and subjective sleep statuses, which determined that the installation of an air conditioner and lighting equipment might affect sleep, may be useful to discuss sleep environments and improve sleep quality.
University of Tsukuba, Graduate School of Comprehensive Human Sciences, Doctoral Program in Human Care Science, Japan. Electronic address: momoko.kayaba@gmail.com.
Momoko
M
Kayaba
The University of Tokyo, Graduate School of Frontier Sciences, Department of Environment Systems, Japan.
Tomohiko
T
Ihara
University of Tsukuba, Center for Computational Sciences, Japan.
Hiroyuki
H
Kusaka
Nagoya University, Graduate School of Environmental Studies, Department of Environmental Engineering and Architecture, Japan.
Satoru
S
Iizuka
Planning Department, Tajimi City, Japan.
Kenji
K
Miyamoto
University of Tsukuba, Faculty of Health and Sports Sciences, Japan.
Yasushi
Y
Honda
D000328:Adult; D000368:Aged; D000389:Air Conditioning / Q000009:adverse effects; D004777:Environment; D005260:Female; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008029:Lighting / Q000009:adverse effects; D008297:Male; D008875:Middle Aged; D009622:Noise / Q000009:adverse effects; D012111:Residence Characteristics / Q000706:statistics & numerical data; D012307:Risk Factors; D012621:Seasons; D012890:Sleep; D012893:Sleep Wake Disorders / Q000453:epidemiology / Q000209:etiology; D011795:Surveys and Questionnaires; D055815:Young Adult
Air conditioner; Environment; Pittsburgh Sleep Quality Index; Questionnaire; Sleep; Summertime