Winter Can Be Dangerous

The two leading causes of mortality worldwide are heart failure and coronary artery disease. The increase in prevalence of these diseases is associated with aging in both low and middle income countries. On the other hand, high income countries which exhibit drastic seasonal changes show a correlation between cardiovascular diseases and winter. The changes in the body that may account for the increased risk of cardiovascular disease in winter consists of higher blood pressure, increased fight-or-flight response, and higher occurrences of respiratory diseases. Other problematic outcomes winter brings include decreased physical activity, increased pollution levels, shorter days, and depression.

The purpose of this study was to investigate any correlation between hospitalization from heart failure or acute myocardial infarction, with respects to average monthly temperatures in Brazil – Sao Paulo. It was predicted that cardiovascular risk was associated with winter even if there weren’t any drastic seasonal changes, and that socio-economic circumstances may be the root of this association.

To gather all the information for this study, observations and retrospective data was used. This included hospitalization records pulled from several hospitals in Brazil for almost a decade. The season averages were established by taking daily measurements of the temperature and averaging them for each month. From this data, it was stated that approximately 76 000 admissions were attributed to heart failure, and 54 000 were due to acute myocardial infarction. In comparison to summer, the occurrences of these diseases peaked much more in the winter season. This was especially true for those above the age of 40 and 50, regardless of gender. This study concluded that there are observable effects winter has on these diseases, but this association does not hold with respects to hospitalization and temperature. This speaks to specific problem regarding winter in Brazil, as the winters consist of limited rain and low humidity which proceed to trap pollution making it harder to disperse.

Taking a look from a socio-economic status (SES) perspective, many people living in Sao Paulo face unreliable housing, extreme traffic, and terrible pollution. These factors become increasingly significant in winter for low-income citizens even with milder temperatures. Therefore this study states that the risk of cardiovascular disease should be emphasized for low to middle income countries in winter as well, even with mild seasonal fluctuations.

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Source:

• Levin, R. K., Katz, M., Saldiva, P. H., Caixeta, A., Franken, M., Pereira, C., . . . Pesaro, A. E. (2018). Increased hospitalizations for decompensated heart failure and acute myocardial infarction during mild winters: A seven-year experience in the public health system of the largest city in Latin America. Plos One,13(1). doi:10.1371/journal.pone.0190733