The Impact of the February 2012 Cold Spell on Health in Italy Using Surveillance Data

Michela Leone,Francesca K. de'Donato,Damia Noce,Paola Michelozzi,Joan A. Caylà,Marina Davoli

doi:10.1371/journal.pone.0061720

Michela Leone, Francesca K. de'Donato + Show 4 more

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https://doi.org/10.1371/journal.pone.0061720

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Journal: PLoS ONE	Publication Date: Apr 18, 2013
Citations: 72	License type: CC BY 4.0

Affiliation: National Centre for Disease Prevention and Control

Abstract

In February 2012 Italy was hit by an exceptional cold spell with extremely low temperatures and heavy snowfall. The aim of this work is to estimate the impact of the cold spell on health in the Italian cities using data from the rapid surveillance systems. In Italy, a national mortality surveillance system has been operational since 2004 in 34 cities for the rapid monitoring of daily mortality. Data from this system were used to evaluate the impact of the February 2012 cold spell on mortality shortly after the occurrence of the event. Furthermore, a cause-specific analysis was conducted in Roma using the Regional Mortality Registry and the emergency visits (ER) surveillance system. Cold spell episodes were defined as days when mean temperatures were below the 10th percentile of February distribution for more than three days. To estimate the impact of the cold spell, excess mortality was calculated as the difference between observed and daily expected values. An overall 1578 (+25%) excess deaths among the 75+ age group was recorded in the 14 cities that registered a cold spell in February 2012. A statistically significant excess in mortality was observed in several cities ranging from +22% in Bologna to +58% in Torino. Cause-specific analysis conducted in Roma showed a statistically significant excess in mortality among the 75+ age group for respiratory disease (+64%), COPD (+57%), cardiovascular disease +20% ischemic heart disease (14%) and other heart disease (+33%). Similar results were observed for ER visits. Surveillance systems need to become are a key component of prevention plans as they can help improve public health response and are a valid data source to rapidly quantify the impact on health. Cold-related mortality is still an important issue and should not be underestimated by public health Authorities.

Highlights

Between January and February 2012 cold polar air from Siberia brought extremely low temperatures and heavy snowfall across most of Europe [1]
The persistence of the cold spell ranged from 16–18 days in northern cities to 7–15 days in central cities, in the south only a few cities registered a cold spell which was generally or shorter duration
Temperatures during the cold spell were much colder in the north and central areas while in southern areas the differences were less discernible

Summary

Introduction

Between January and February 2012 cold polar air from Siberia brought extremely low temperatures and heavy snowfall across most of Europe [1]. In Italy, a rapid mortality surveillance system was set up in 2004 in collaboration with Municipal Registry Offices to evaluate the impact of heat waves on health during summer [9]. This system was gradually extended to cover the whole year and to date has permitted the routine evaluation of heat waves throughout the summer as well as the timely evaluation of other extreme events like the cold spell of February 2012. In the literature there are several case studies of the use of ER visits for monitoring and evaluating the effects of heat waves on non-fatal health outcomes [8,11,12,13]. The surveillance of morbidity indicators are of great importance in public health to plan prevention strategies and define preparedness protocols to cope with emergencies

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