Associations of day-to-day temperature change and diurnal temperature range with out-of-hospital cardiac arrest

Abstract

Background

Although the impacts of temperature on mortality and morbidity have been documented, few studies have investigated whether day-to-day temperature change and diurnal temperature range (DTR) are independent risk factors for out-of-hospital cardiac arrest (OHCA).

Design

This was a prospective, population-based, observational study.

Methods

We obtained all OHCA data from 2005–2013 from six major prefectures in Japan: Hokkaido, Tokyo, Kanagawa, Aichi, Kyoto, and Osaka. We used a quasi-Poisson regression analysis with a distributed-lag non-linear model to assess the associations of day-to-day temperature change and DTR with OHCA for each prefecture.

Results

In total, 271,698 OHCAs of presumed cardiac origin were reported during the study period. There was a significant increase in the risk of OHCA associated with cold temperature in five prefectures, with relative risks (RRs) ranging from 1.298 (95% confidence interval (CI) 1.022–1.649) in Hokkaido to 3.893 (95% CI 1.713–8.845) in Kyoto. DTR was adversely associated with OHCA on hot days in Aichi (RR 1.158; 95% CI 1.028–1.304) and on cold days in Tokyo (RR 1.030; 95% CI 1.000–1.060), Kanagawa (RR 1.042; 95% CI 1.005–1.082), Kyoto (RR 1.060; 95% CI 1.001–1.122), and Osaka (RR 1.050; 95% CI 1.014–1.088), whereas there was no significant association between day-to-day temperature change and OHCA.

Conclusion

We found that associations between day-to-day temperature change and DTR and OHCA were generally small compared with the association with mean temperature. Our findings suggest that preventative measures for temperature-related OHCA may be more effective when focused on mean temperature and DTR.