Temperature, air pollution, and mortality from myocardial infarction in São Paulo, Brazil

Abstract

An increase in daily mortality from myocardial infarction has been observed in association with meteorological factors and air pollution in several cities in the world, mainly in the northern hemisphere. The objective of the present study was to analyze the independent effects of environmental variables on daily counts of death from myocardial infarction in a subtropical region in South America. We used the robust Poisson regression to investigate associations between weather (temperature, humidity and barometric pressure), air pollution (sulfur dioxide, carbon monoxide, and inhalable particulate), and the daily death counts attributed to myocardial infarction in the city of São Paulo in Brazil, where 12,007 fatal events were observed from 1996 to 1998. The model was adjusted in a linear fashion for relative humidity and day-of-week, while nonparametric smoothing factors were used for seasonal trend and temperature. We found a significant association of daily temperature with deaths due to myocardial infarction (P < 0.001), with the lowest mortality being observed at temperatures between 21.6 and 22.6ºC. Relative humidity appeared to exert a protective effect. Sulfur dioxide concentrations correlated linearly with myocardial infarction deaths, increasing the number of fatal events by 3.4% (relative risk of 1.03; 95% confidence interval = 1.02-1.05) for each 10 µg/m 3 increase. In conclusion, this study provides evidence of important associations between daily temperature and air pollution and mortality from myocardial infarction in a subtropical region, even after a comprehensive control for confounding factors.

Air quality in the megacity of São Paulo: Evolution over the last 30 years and future perspectives

“…corresponds to an increase of 3.4% in the number of deaths from myocardial infarction (Sharovsky et al, 2004). Gonçalves et al (2007) presented similar results, in which the determination of the impacts of PM 10 and SO 2 , as well as thermal comfort indices, were found to be the best tools for comparing weather and pollutants with cardiovascular mortality and morbidity in the MASP.…”

Impact of urban atmospheric environment on hospital admissions in the elderly

“…Other studies conducted in São Paulo also reported a relationship between colder days and an increase in circulatory diseases. 7,20 The etiology of circulatory system diseases is complex and some risk factors include hypertension, smoking, dyslipidemia, diabetes, and obesity. Stressful psychosocial factors as work-related stress, sadness, depression, anxiety, and strain have been associated with greater risk of myocardial infarction.…”

Short term effects of temperature on risk of myocardial infarction in England and Wales: time series regression analysis of the Myocardial Ischaemia National Audit Project (MINAP) registry

“…Two studies that did address all of these methodological concerns were those of data on myocardial infarction related mortality, which found a detrimental effect of heat 20 or of both heat and cold. 21 Such data may, however, have poor specificity because in a proportion of cases the myocardial infarction diagnosis is likely to be assumed; therefore these findings in reality may reflect temperature effects on more broad health outcomes. In contrast, of five studies that analysed validated myocardial infarction outcomes separately, only one based in a subarctic area reported a detrimental heat effect, 22 most reporting an adverse effect only of cold.…”