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Volume 8, Issue 10 (Suppl) J Earth Sci Clim Change, an open access
ISSN: 2157-7617 Climate Change 2017
October 19-21, 2017
CLIMATE CHANGEOctober 19-21, 2017 | Rome, Italy
4 th World Conference on
Associations of temperature variation and mortality in seven Japanese prefectures
Chaochen Ma1, Daisuke Onozuka2, Chris Fook Sheng Ng3, Xerxes Tesoro Seposo1, Tran Ngoc Dang1 and Yasushi Honda 1
1University of Tsukuba, Japan
2Kyushu University, Japan
3Nagasaki University, Japan
Purpose: Few studies have investigated the mortality effects of temperature variation (TV) in Japan. In this study, we used the
newly proposed indicators of inter- and intra-day TVs to assess the TV-mortality associations and compare the associations
with the contribution of mean daily temperature.
Methods: We collected daily data for temperature and mortality during 1972-2012 from seven major prefectures in Japan,
i.e., Hokkaido, Yamagata, Tokyo, Kanagawa, Aichi, Osaka, and Fukuoka. We performed a quasi-Poisson regression analysis
combined with a distributed-lag non-linear model. We separated the effect of inter- and intra-day TVs into cold- and heat-
related, by calculating only those below and above the minimummortality temperature (MMT), respectively. The inter-day TV
was defined as the relative change in temperature between the current and previous day. The intra-day TV (diurnal temperature
range (DTR)) was calculated as the difference between the daily maximum and minimum temperature.
Results: All prefectures showed significant increases in mortality risk associated with mean daily temperature, with a relative
risk (RR) reaching 1.148 (95% confidence interval (CI): 1.108, 1.190) for heat in Aichi and 1.462 (95% CI: 1.295, 1.650) for cold
in Yamagata. In contrast, inter- and intra-day TVs were mostly insignificant and the effect size was small, with less than 2%
risk. DTR was adversely associated with mortality on hot days in Tokyo (RR 1.014; 95% CI: 1.004, 1.025), and Kanagawa (RR
1.014; 95% CI: 1.000, 1.029), and on cold days in Tokyo (RR 1.005; 95% CI: 1.001, 1.010).
Conclusions: We found that the association between mortality and temperature variation is generally small compared with
mean daily temperature, although further research is necessary.
Biography
Chaochen Ma is currently pursuing his PhD in University of Tsukuba, Japan. His major is on environmental epidemiology with an interest in the associations of
temperature and mortality or mobility, and quantify the effect.
Chaochen Ma et al., J Earth Sci Clim Change 2017, 8:10(Suppl)
DOI: 10.4172/2157-7617-C1-037