Smoking a single cigarette per day aumente the risk of heart attack and STROKE
Published the 26.01.2018 at 19h01
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Smoking a single cigarette per day represents a much higher risk to develop coronary heart disease or a stroke than expected. As soon as the first cigarette, it was already half the risk of smoking is equal to smoking 20 cigarettes per day. This is what emerges from an analysis of many studies published by the BMJ. The risk would be nearly 50% of the risk from smoking a packet per day in men and third in women.
This result has important consequences for many smokers and health professionals believe that smoking only a few cigarettes per day is less bad than smoking a pack. Their recommendation is that smokers should stop smoking for good instead of seeking only to reduce their risk of heart disease and STROKE significantly.
Less than 6 cigarettes, it is for the lung
In terms of tobacco, there is a great variability in individual susceptibility due to genetic and associated risk factors.
For the risk of chronic bronchitis or lung cancer, a linear relationship between cigarette consumption and the risk of being objectified : it has been shown that smoking less than 6 cigarettes per day would be significantly less toxic for the lungs.
It is not the same for the heart, where several studies conducted on individual-level data have shown that smoking only five cigarettes per day is associated with a higher risk than expected from cardiovascular diseases (heart attack and STROKE).
For the heart, it is from the 1st cigarette
To further investigate this question, a team of researchers led by professor Allan Hackshaw, UCL Cancer Institute, University College London, analyzed the results of 141 studies and estimated relative risks of smoking one, five or 20 cigarettes per day.
Compared to the risks observed in men who smoke one pack of cigarettes per day (20), men who smoke one cigarette per day still have 46% of the risk of heart disease, and 41% of that of a STROKE. A risk much higher than the 5% which would have been able to mathematically expect. Among women, those who smoke only one cigarette per day still have a 31% risk of heart disease and 34% risk of STROKE compared to the risk associated with 20 cigarettes per day.
Only the withdrawal reduces the risk
“We have shown that a large part of the risk of coronary heart disease and stroke exists with only a few cigarettes per day “, say the authors. “This surprises probably a lot of people, but there are also biological mechanisms which help to explain the unforeseen risk associated with a low rate of smoking “.
Indeed, cardiac studies earlier have shown that the mechanism of toxicity is not the same in the lung than in the heart. If in the bronchi, it is a mechanism irritatif, each cigarette prolonging the irritation and inflammation of the bronchi of the previous one, in the heart, there is also a direct action on platelets, those small elements in circulating blood that are normally responsible for the clotting. A single cigarette has a tendency to excite the pads and make them hyperactive. All of this leads us to a state of hypercoagulability that increases the risk of a blood clot (thrombus) in the arteries, particularly the coronary.
Therefore, there is no level of smoking safe for the heart disease : the only complete weaning is protective and should be the goal of all prevention policies. In passing, the risk associated with this low level of consumption explains the harmfulness of passive smoking.