Onozuka, D. and Hagihara, A. 2015. All-Cause and Cause-Specific Risk of Emergency Transport Attributable to Temperature. Medicine 94: e2259.
In an intriguing study conducted in Japan, Onozuka and Hagihara (2015) acquired data on daily emergency ambulance dispatches throughout all 47 of the country's prefectures from 2007 to 2010, which they used to determine relationships between medical emergency transport and temperature for each of the country's prefectures. This they did using "a Poisson regression model in a distributed lag nonlinear model with adjustment for time trends," after which "a random-effect multivariate meta-analysis was used to pool the estimates at the national level. And what did they learn by so doing?
The two Japanese researchers report that the fraction of ambulance dispatches attributable to low temperatures was 6.94% for all causes, while that attributable to high temperatures was 1.01% for all causes, which results clearly show -- as they report -- that "the majority of temperature-related emergency transport burden was attributable to lower temperature," which burden was almost seven times greater than that attributable to higher temperatures. And thus whatever degree of global warming the Earth may experience in future years, humanity should significantly benefit from it in terms of experiencing a significantly reduced number of illnesses of various types that may elicit emergency transport to hospitals.
An example of the relationship between human morbity and temperature from the study of Onozuka and Hagihara (2015). This figure displays the overall cumulative exposure–response associations between the relative risks (RR) (95%CI) for all-cause morbidity (left panel), caridovascular-related morbidity (center panel) and respiratory morbidity (right panel) and temperatures in the Fukuoka Prefecture, Japan. As illustrated, the relative risk of morbidity at lower temperatures is far greater than the relaive risk at high temperatures.