Researchers from the Institute of Social and Preventive Medicine, University of Lausanne (IUMSP) revealed that the cardiovascular risks increase in the cold weather. The new multinational study was based on the cross-sectional data of ten studies from more than seven countries. The researchers explained that the risk factors of heart attack occur more in the winter season than the summer.
Dr. Pedro Marques-Vidal of Institute of Social and Preventive Medicine, University of Lausanne (IUMSP) explained that the deaths occurring from cardiovascular disease are more in winter and much lower in summer. The study was therefore undertaken to study the seasonal patterns of the cardiovascular risks.
In order to conduct the research, the information was obtained from 107090 subjects between the ages of 35 and 80. The countries with their respective numbers of patients were 21128 in Belgium, 15664 in Denmark, 1626 in France, 18370 in Italy, 25532 in Norway, 9359 in Russia and 15411 in Switzerland.
Risk Factors that lead to cardiovascular diseases
The researchers, during the study made a comparison of the factors such as waist circumference, BMI, glucose, lipids as well as blood pressure for every season. The entire data was adjusted on the basis of smoking, gender and age. Certain data such as glucose, lipids and BP, were adjusted for the BMI or on whether the patient was on some medication or not.
The research team found out that various risk factors were more during January and February, i.e., during the winter season. These risk factors were comparatively lower from June to August, i..e., during the summer season. The systolic blood pressure levels were around 3.5 mmHg lower in the summer months than in the winter on an average.
Dr. Pedro Marques-Vidal explained that though the difference was irrelevant for the individual but it was crucial for the overall population because the entire blood pressure distribution shifted to the higher values, thereby increasing the cardiovascular risks. Therefore, the impact of the season on blood pressure would be much higher on the cardiovascular risks. This is so because the combined impact of genetic markers on blood pressure was modest, i.e., between 2 and 3 mmHg.
It was also found that the waist circumference, on an average was 1 cm (0.4 in) smaller in the summer months than the winter months. Likewise, in another factor, the overall cholesterol was 0.24 mmol/L lower in the months of summer in comparison to the winter.
It is for all these reasons that people have to work out higher in the winter than in the summer. Extra effort need to be done for exercising and eating healthy. In another study, it was found whether seasonal pattern in the cardiovascular risk factors reverse in southern hemisphere, where the seasons are also reversed in relation to the northern hemisphere. The complete study would collect the information on around 200000 subjects from more than 12 countries of the world.
The team of researchers was also conducting the study across 18 different countries, which involves 50 million deaths.
Air Pollution as a factor
In yet another related study, it was found out about what relation air pollution had with the heart attacks. Prof. Marc Claeys of Belgium in his study explained that there were no direct links between these two. His study involved 16000 patients.
It is important to note that temperature changes as well as air pollution are most reported environmental factors which are responsible for acute myocardial infarction (AMI). Better understanding and knowledge about the impact of environment on AMI will enable the medical care providers as well as policy-makers to optimise the prevention strategies for risk population.
The study also found out about the independent environmental triggers of AMI. In the study, the researchers extracted the data from 32 Belgian percutaneous coronary intervention (PCI) centres from the year 2006 to 2009. During this time, the weekly counts of AMI patients who went through the primary PCIs, was studied.
These AMI counts were related with the average weekly meteorological data which was obtained from the daily measurements in the 73 different meteorological sites in Belgium. The team of researchers investigated the measurements from the temperature, relative humidity, black smoke as well as the air pollution.