Whanhee Lee1, Yeonseung Chung2, Hayon Michelle Choi1, Dahye Kim1, Yasushi Honda3, Yue-Liang Leon Guo4, Ho Kim5. 1. Department of Public Health Science, Graduate School of Public Health, Seoul National University, Seoul, Republic of Korea. 2. Department of Mathematical Sciences, Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea. 3. Faculty of Health and Sports Sciences, University of Tsukuba, Tsukuba, Japan. 4. Department of Environmental and Occupational Medicine, National Taiwan University (NTU) and NTU Hospital, Taipei, Taiwan. 5. Institute of Health and Environment, Seoul National University, Seoul, Republic of Korea.
Abstract
BACKGROUND: The diurnal temperature range (DTR) represents temperature variability within a day and has been reported as a potential risk factor for mortality. Previous studies attempted to identify the role of temperature in the DTR-mortality association, but results are inconclusive. The aim of this study was to investigate the interactive effect of temperature and DTR on mortality using a multicountry time series analysis. METHODS: We collected time series data for mortality and weather variables for 57 communities of three countries (Taiwan, Korea, and Japan) in Northeast Asia (1972-2012). Two-stage time series regression with a distributed lag nonlinear model and meta-analysis was used to estimate the DTR-mortality association changing over temperature strata (six strata were defined based on community-specific temperature percentiles). We first investigated the whole population and then, the subpopulations defined by temperature distribution (cold and warm regions), sex, and age group (people <65 and ≥65 years of age), separately. RESULTS: The DTR-mortality association changed over temperature strata. The relative risk (RR) of mortality for 10°C increase in DTR was larger for high-temperature strata compared with cold-temperature strata (e.g., = 1.050; 95% confidence interval [CI] = 1.040, 1.060 at extreme-hot stratum and RR = 1.040; 95% CI = 1.031, 1.050 at extreme-cold stratum); extreme-hot and -cold strata were defined as the days with daily mean temperature above 90th and below 10th percentiles each community's temperature distribution. Such increasing pattern was more pronounced in cold region and in people who were 65 years or older. CONCLUSIONS: We found evidence that the DTR-related mortality may increase as temperature increases.
BACKGROUND: The diurnal temperature range (DTR) represents temperature variability within a day and has been reported as a potential risk factor for mortality. Previous studies attempted to identify the role of temperature in the DTR-mortality association, but results are inconclusive. The aim of this study was to investigate the interactive effect of temperature and DTR on mortality using a multicountry time series analysis. METHODS: We collected time series data for mortality and weather variables for 57 communities of three countries (Taiwan, Korea, and Japan) in Northeast Asia (1972-2012). Two-stage time series regression with a distributed lag nonlinear model and meta-analysis was used to estimate the DTR-mortality association changing over temperature strata (six strata were defined based on community-specific temperature percentiles). We first investigated the whole population and then, the subpopulations defined by temperature distribution (cold and warm regions), sex, and age group (people <65 and ≥65 years of age), separately. RESULTS: The DTR-mortality association changed over temperature strata. The relative risk (RR) of mortality for 10°C increase in DTR was larger for high-temperature strata compared with cold-temperature strata (e.g., = 1.050; 95% confidence interval [CI] = 1.040, 1.060 at extreme-hot stratum and RR = 1.040; 95% CI = 1.031, 1.050 at extreme-cold stratum); extreme-hot and -cold strata were defined as the days with daily mean temperature above 90th and below 10th percentiles each community's temperature distribution. Such increasing pattern was more pronounced in cold region and in people who were 65 years or older. CONCLUSIONS: We found evidence that the DTR-related mortality may increase as temperature increases.
Authors: Whanhee Lee; Yoonhee Kim; Francesco Sera; Antonio Gasparrini; Rokjin Park; Hayon Michelle Choi; Kristi Prifti; Michelle L Bell; Rosana Abrutzky; Yuming Guo; Shilu Tong; Micheline de Sousa Zanotti Stagliorio Coelho; Paulo Hilario Nascimento Saldiva; Eric Lavigne; Hans Orru; Ene Indermitte; Jouni J K Jaakkola; Niilo R I Ryti; Mathilde Pascal; Patrick Goodman; Ariana Zeka; Masahiro Hashizume; Yasushi Honda; Magali Hurtado Diaz; Julio César Cruz; Ala Overcenco; Baltazar Nunes; Joana Madureira; Noah Scovronick; Fiorella Acquaotta; Aurelio Tobias; Ana Maria Vicedo-Cabrera; Martina S Ragettli; Yue-Liang Leon Guo; Bing-Yu Chen; Shanshan Li; Ben Armstrong; Antonella Zanobetti; Joel Schwartz; Ho Kim Journal: Lancet Planet Health Date: 2020-11