Though most people now understand that smoking can be a very harmful habit over the long run, some folks believe they are protected from harm if they smoke “just a few” cigarettes each day. Unfortunately, there really is no low level of smoking that can be said to be completely safe for any given person. In fact, in some circumstances, just one cigarette can be harmful!! First, let’s talk about a concept called the “dose-response” relationship. Basically, this means that if a small dose of a medication has a small amount of benefit, then a larger dose of that medication will have a larger benefit. This is true for the majority of prescription as well as over-the-counter medications. You probably already know that two aspirin will have a greater effect on your headache than just one. In the case of medications, there is usually a maximum dose that gives maximum benefit, and going to an even higher dose only produces side effects. For example, a dose of three aspirin won’t work any better for your headache than two aspirin and is much more likely to upset your stomach. When we use the “dose-response” relationship to talk about the risks of smoking, we use cigarettes per day as the measure of dose, and we measure the adverse effects rather than benefit. For the majority of medical problems that are caused by smoking, researchers have been able to identify that there is a definite relationship between the “dose” (in this case, cigarettes per day) and the adverse effects. The higher the “dose”, the greater the negative effects. Let’s talk about lung function as an example. All individuals will have a decrease in lung capacity as they get older. However, heavy smokers lose their lung capacity more quickly than moderate smokers and moderate smokers lose their lung capacity more quickly than light smokers. It’s important to note, however, that even light smokers lose lung capacity more rapidly than non-smokers do! In this example, it is clear that someone who smokes “just a few” is better protected from loss of lung function than a heavy smoker, but there is no specific low level of cigarettes per day that can be said to be as safe as not smoking at all! Lung cancer is another example where researchers have identified a clear dose-response relationship between cigarettes per day and risk for developing cancer. Heavy smokers are at the highest risk, moderate smokers are at moderate risk, and light smokers are at lowest risk. But all active smokers are at greater risk for lung cancer than non-smokers! Even passive smokers (people who have second-hand exposure to tobacco smoke) are at higher risk than people who have no exposure at all. In the example of lung cancer, a person who smokes “just a few” will be at lower risk than a moderate or heavy smoker, but that person will still have more risk for developing lung cancer than a non-smoker. And there is no such thing as “just a little” lung cancer. Once you have cancer, you have cancer – and being a light smoker does not necessarily mean that you will have a greater chance for cure than any other person who has lung cancer. Now, let’s talk about the situation where even one cigarette can be harmful. In this case, we are talking about the acute effects of smoking, rather than the long-term effects that build up over time. Smoking just a single cigarette causes platelets in your blood to become sticky and they are thus more likely to block tiny blood vessels. Many other measurable changes occur with each single cigarette - the heart rate increases a bit, blood pressure increases a bit, blood vessels which supply the heart muscle constrict a bit, and carbon monoxide levels in the blood increase a bit. All of these changes together can significantly increase the stress to the heart muscle. Even more importantly, these changes and the additional stress can cause an acute heart attack in a person who may already have some blockages in his/her coronary arteries. Once the heart attack has occurred, the damage is done. It doesn’t really matter if it was just one out of only five cigarettes per day or one out of forty cigarettes per day that led to the specific heart attack. The good news here is that research has shown that a person who already has blockages can significantly reduce his/her risk for heart attack by quitting smoking. Quitting doesn’t make the heart disease or the blockages go away, but it does remove the acute stresses imposed by each and every cigarette. Researchers who have studied the effects of second-hand smoking have made the strongest arguments against the idea that smoking “just a few” cigarettes is safe. When compared to non-smokers, passive smokers have been shown to have more lung cancers, more heart disease, and more heart attacks. Even young, otherwise healthy adults with passive smoke exposure have been shown to have early signs of damage to the lining of their arteries that are not seen in people who have no exposure to tobacco smoke at all. Since even passive smokers have been shown to have arterial damage and higher risk for several smoking related problems, then active smokers who smoke “just a few” cigarettes must certainly be at risk as well. When it comes to smoking, there just is no level that can be considered safe!!
|
