Emergency Hospital Admissions for Cardiovascular Causes Attributable to Air Pollution and Extreme Temperatures in Spain: Influence of Economic and Demographic Factors in a Nationwide Study.

Abstract

Using generalised linear models (GLMs) with a Poisson link, this study analysed the short-term effect of NO₂, ozone, PM₁₀ and PM_2.5 on the daily number of emergency hospital admissions due to cardiovascular disease (CVD), acute cerebrovascular disease, acute myocardial infarction (AMI) and ischaemic heart disease (IHD). The impact of the minimum daily temperature in cold waves and maximum daily temperature in heat waves was likewise analysed. Specific dose-response functions were calculated for each province and cause of admission considered. We used random effects mixed models to analyse the relationship between the percentage of admissions in each province and the following provincial variables: income level; number of inhabitants; population percentage aged 65 years and over and percentage of women. Our results indicated that in Spain there were 10,167 (95%CI: 3.679, 16.554) emergency CVD-related annual admissions attributable to the variables considered, which accounted for 7.7% of total annual CVD-related admissions in Spain and broke down as follows: 6.9% attributable to air pollution in general, and NO₂ and O₃ in particular, and 0.8% attributable to extreme temperatures, especially during cold waves. A similar pattern could be observed for the specific causes. With respect to the percentage of CVD-related admissions attributable to air pollution, higher income level was a protective element and age over 65 years was a risk factor for the percentage of the population concerned. Air pollution is a risk factor for short-term emergency hospital admissions due to CVD in Spain, with the effect NO₂ and O₃ being especially noteworthy, in terms of all CVD-related causes and the specific causes considered. The impact of extreme temperatures is of a lower order of magnitude than that of air pollution, and the effect of the maximum daily temperature in heat waves on CVD is extremely small.