Hot Truth about Cold Weather- Peer reviewed papers - Cold weather kills 20 times more people than hot weather

A peer reviewed paper published in Environment International:

Geographical variation in relative risks associated with cold waves in Spain: The need for a cold wave prevention plan. Carmona et al  2016 Mar;88:103-11. doi: 10.1016/j.envint.2015.12.027. Epub 2015 Dec 29


(bold added)

In general, there are few studies that analyse the impact of low temperatures on mortality and fewer still that use cold-wave-definition thresholds based on epidemiological and non-climatological criteria. Such a threshold definition, which took into account population features such as socio-economic and demographic characteristics, made it possible for a specific threshold temperature to be obtained for each of Spain's 52 provincial capitals in this study. Using generalised linear models with the Poisson regression link, and controlling for trend, autocorrelations and seasonalities of the series, and influenza epidemics, we obtained the impact of low temperatures on mortality in each provincial capital by calculating the relative risks (RRs) and attributable risks (ARs) for natural as well as circulatory and respiratory causes. The study showed higher minimum temperature thresholds in coastal areas, and an overall impact of cold on mortality in Spain due to natural causes RR=1.13 (95% CI: 1.11-1.16), circulatory causes RR=1.18 (95% CI: 1.15-1.22) and respiratory causes RR=1.24 (95% CI: 1.20-1.29) slightly greater than that obtained to date for heat. From a public health standpoint, there is a need for specific cold wave prevention plans at a regional level which would enable mortality attributable to low temperatures to be reduced. These plans have shown themselves to be effective in decreasing heat-related mortality, and we feel that they are essential for reducing cold-related effects on morbidity and mortality.
What does this mean?
CO2 Science note:
In setting the stage for reporting their study of this important topic, Carmona et al. (2016) make a point of noting that "studies undertaken in the United Kingdom, Australia and the Netherlands indicate that cold-related deaths are an order of magnitude greater than those related to heat," citing Vardoulakis et al. (2014) and Huynen et al. (2001), while further noting that the life-robing effect of low temperatures at ground level is "20 times, and in the case of Spain, 5 times greater than that of heat," citing the work of Gasparrini et al. (2015). 
In their more recent study of the subject, the six Spanish scientists determined the impact of daily minimum temperatures on mortality in each of Spain's 52 provincial capitals; and they report that this effort revealed relative cold-induced mortality increases of 1.13 due to natural causes, 1.18 due to circulatory causes, and 1.24 due to respiratory causes, which numbers they found to be "slightly greater than those obtained to date for heat."
This follows a paper from the Lancet (Can the Lancet be trusted?) in May 2015:

Cold weather kills far more people than hot weather

Gasparrini et al: Mortality risk attributable to high and low ambient temperature: a multicountry observational study. The Lancet, May 2015 DOI: 10.1016/S0140-6736(14)62114-0

Cold weather kills 20 times as many people as hot weather, according to an international study analyzing over 74 million deaths in 384 locations across 13 countries. The findings, published in The Lancet, also reveal that deaths due to moderately hot or cold weather substantially exceed those resulting from extreme heat waves or cold spells. 
"It's often assumed that extreme weather causes the majority of deaths, with most previous research focusing on the effects of extreme heat waves," says lead author Dr Antonio Gasparrini from the London School of Hygiene & Tropical Medicine in the UK. "Our findings, from an analysis of the largest dataset of temperature-related deaths ever collected, show that the majority of these deaths actually happen on moderately hot and cold days, with most deaths caused by moderately cold temperatures."