Mean air temperature as a risk factor for stroke mortality in São Paulo, Brazil.

In Brazil, chronic diseases account for the largest percentage of all deaths among men and women. Among the cardiovascular diseases, stroke is the leading cause of death, accounting for 10% of all deaths. We evaluated associations between stroke and mean air temperature using recorded mortality data and meteorological station data from 2002 to 2011. A time series analysis was applied to 55,633 mortality cases. Ischemic and hemorrhagic strokes (IS and HS, respectively) were divided to test different impact on which subgroup. Poisson regression with distributed lag non-linear model was used and adjusted for seasonality, pollutants, humidity, and days of the week. HS mortality was associated with low mean temperatures for men relative risk (RR) = 2.43 (95% CI, 1.12-5.28) and women RR = 1.39 (95% CI, 1.03-1.86). RR of IS mortality was not significant using a 21-day lag window. Analyzing the lag response separately, we observed that the effect of temperature is acute in stroke mortality (higher risk among lags 0-5). However, for IS, higher mean temperatures were significant for this subtype with more than 15-day lag. Our findings showed that mean air temperature is associated with stroke mortality in the city of São Paulo for men and women and IS and HS may have different triggers. Further studies are needed to evaluate physiologic differences between these two subtypes of stroke.

Association between climate variables, pollutants, aerosols and hospitalizations due to asthma / Association between climate variables, pollutants, aerosols and hospitalizations due to asthma

Many studies have shown that climatic and pollutant variables are directly related to the increase of hospitalizations due to respiratory diseases, mainly asthma. The aim of this study was to estimate the association between exposure to climate variables, pollutants, aerosols and hospitalizations due to asthma. This ecological study used time series with daily asthma hospitalization indicators, and concentrations of pollutants, climate data and aerosols, between January 2013 and December 2013. A generalized additive model using Poisson regression was used to estimate the relative risk with a two-day lag after exposure; the unipollutant model was adjusted by the apparent temperature, a measure defined from the temperature and relative humidity of the air, and a variable was added to control the seasonality and the day of the week. As a result, the values of relative risks (RR) for hospitalizations due to asthma were: for minimum temperature RR= 0.8985; maximum humidity RR= 0.9819; wind speed RR= 0.9419; rain RR= 0.9834; ozone RR= 0.9735; aerosols (AOT) RR= 1.0078; clearness index (Kt) RR= 0.0492 and carbon monoxide RR= 1.0865 for a two-day lag. After considering the aforementioned factors, we found the values of B coefficients. Exposure to climatic variables, pollutants, aerosols and clearness index was associated with hospitalizations due to asthma, and provided subsidies for the implementation of preventive measures to decrease these outcomes

Muitos estudos vêm demonstrando que variáveis climáticas e poluentes tem uma relação direta no aumento de internações por doenças respiratórias, principalmente por asma. O objetivo deste estudo foi estimar a associação entre exposição às variáveis climáticas, poluentes, aerossóis nas internações por asma. O presente estudo ecológico utilizou séries temporais com indicadores diários de internação por asma, e concentrações de poluentes, dados de clima e aerossóis, entre janeiro de 2013 e dezembro de 2013. Um modelo aditivo generalizado utilizando regressão de Poisson foi usado para estimar o risco relativo, com defasagem de dois dias após a exposição; o modelo unipoluente foi ajustado pela temperatura aparente, medida definida a partir da temperatura e umidade relativa do ar, foi adicionada uma variável para controlar a sazonalidade e o dia da semana. Como resultados, os valores dos riscos relativos para internações por asma foram para Temperatura mínima: RR=0,8985; umidade máxima RR=0,9819; velocidade dos ventos RR=0,9419; precipitação RR= 0,9834; ozônio RR=0,9735; aerossóis (AOT; RR=1,0078; índice de claridade (Kt) RR=0,0492 e monóxido de carbono RR=1,0865 para defasagem temporal de dois dias. Após considerar os fatores mencionados, encontramos os valores dos coeficientes B's. A exposição às variáveis climáticas, poluentes, aerossóis e índice de claridade esteve associada às internações por asma, e forneceu subsídios para implantação de medidas preventivas para diminuírem esses desfechos