Geographical and Temporal heterogeneity in the effects of temperature on mortality: Results from multicenter studies Michela Leone, Manuela De Sario, Paola Michelozzi

The Italian Program for prevention of heat health effects Since 2004 (Italian Department for Civil Protection and the Ministry of Health) Includes 34 major cities and focuses on the elderly Integrated approach: Heat Health Watch Warning Systems, prevention activities targeted to susceptible subgroups, mortality surveillance system Real time monitoring, estimate of the effect of heat/heat waves on mortality and of temporal variations (i.e. evaluation of warning systems and prevention programs)

Geographical heterogeneity in 26 Italian cities

Geographical heterogeneity in 10 Mediterranean cities Modification by city characteristics of heat effect on mortality. Comparison of the predicted change in mortality at 25th and 75th percentile of the effect modifier distribution a Meta-regression estimates Leone et al. submitted to Epidemiology

Temporal heterogeneity: open questions Long-term changes in temperature-mortality relationship Interannual changes of the heat effect?

1. Long-term changes in temperature-mortality relationship 16 Italian Cities: MAT (°C)-daily 65+ mortality relationship, summers 1998-2002, 2006-2010 Temperature mortality curve for 65+ population for period 1998-2002 and for the more recent period 2006-2010. A very slight increase in the effect of lower temperatures and a clear reduction of the effect of high temperatures on mortality in the post-intervention period. Also it shows how the upper limit of observed temperatures was lower in the 2006–2010 period

1. Long-term changes in temperature-mortality relationship 16 Italian Cities: 3°C increase in MAT (°C) over the 25° pctile, summers 1998-2002, 2006-2010 Dividing the temperature range into three-degree intervals, for each study period we obtained five temperature intervals and five estimates of the exposure–mortality relationship in terms of percent change in mortality risk Using DLNM models Schifano, Leone et al. Environ Health. 2012 Sep 3;11(1):58

Monthly differences in MAT, summers 1998-2002, 2006-2010 Periodo post più caldo e la stagione si è allungata Schifano, Leone et al. Environ Health. 2012 Sep 3;11(1):58

1. Long-term changes in temperature-mortality relationship 16 Italian Cities: meta-analytic time-varying effects for 1°C increase in MAT , summers 1998-2002, 2006-2010 Schifano et al. Environ Health. 2012 Sep 3;11(1):58

2. Interannual changes of the heat effect? Rome: Tappmax - 65+ yrs mortality curves: summer period (june-august) 2003, 2012, reference period

2. Interannual changes of the heat effect? Bologna: Tappmax - 65+ yrs mortality curves: summers period (june-august) 2003, 2012, reference period

2. Interannual changes of the heat effect? Percent increase in mortality (65+) for 2°C step increase in MAT above the 10th summer percentile.

Temporal heterogeneity: methodological challenges How to define a heat wave (which is the reference?) What is the mortality baseline? How long? What years? Changes in exposure, population susceptibility and adaptive capacity? Effect modification by previous winter mortality?

Changes in the harvesting effect? Linear DLM (5th-order polynomial) at 30 days lag Leone et al. XXXVI Annual Congress Italian Epidemiological Association

Does susceptible population change? Rome: all 65+ yrs resident population, summers 2008-2011 Marino et al. XXXVI Annual Congress Italian Epidemiological Association

What the challenges for epidemiologists in the 21th century? It is very likely/likely that the length, frequency, and/or intensity of heat waves and other extreme weather events (i.e. floods, tropical cyclones, droughts) will increase over most land areas (IPCC SREX 2012 http://www.ipcc-wg2.gov/SREX/) Exposure changes Previous winter mortality effect ? Changes in individual and population susceptibility factors Adaptation measures Socio-demographic changes 16

Ongoing projects At the international level: EU-funded Project (9 cities: Rome, Athens, Helsinki, Budapest, Valencia, Barcelona, Paris, London, Stockholm) Study period 1990-2010 Collaboration with LSHTM (USA, UK, Spain and Italian cities) At the national level: The Italian national program for the prevention of heat health effects in 34 cities Collaboration with EPIAIR II project “Air pollution and health, epidemiological surveillance and prevention” in 15 Italian cities Study period: 2001-2010