What’s a common action among Robert de Niro in “Casino”, Sharon Stone in “Basic Instinct”, Audrey Hepburn in “Breakfast at Tiffany’s” and Clint Eastwood in “The Good, the Bad, and the Ugly”? Leaving aside the unforgettable performances, a peculiarity is that they all smoke in iconic scenes of the movies. What happened next? After Brad Pitt in “Fight Club” it’s difficult to remember other legendary actors smoking on the set.
Of course, because smoking is bad! Now we know it perfectly, but decades ago smoking was just cool.
So, how come tobacco is so dangerous?
First of all, if you use the word “tobacco” and “cigarette” as synonyms, some clarification is needed. What is a cigarette? The definition is a blend of tobacco leafs wrapped in paper. Unfortunately this definition is lacking few hundred ingredients. Some of them give flavor to the cigarette (sugars, cocoa, licorice, fruit extracts and aroma substances), others increase tobacco’s effect (nicotine), resulting in increased addictiveness. In particular, the latter effect is achieved by maintaining an extremely hot temperature of the burning cigarette. This allows nicotine to turn into a vapor so that lungs can absorb it more easily, and the process is speeded up by presence of ammonia. The problem is that dozens of these additives are carcinogenic. Talhout and colleagues, in 2011, published a comprehensive list of additives present in tobacco’s smoke and highlighted a subset of 98 hazardous substances. It is impressive the presence of arsenic (yeah, the poison), formaldehyde (preservative in science laboratories and mortuaries), carbon monoxide (poisonous gas), radioactive elements (that come from the fertilizer and soil used to grow the tobacco leaves), hydrogen cyanide (another poison). I could write pages about them, but you can just click on this Wikipedia link: https://en.wikipedia.org/wiki/List_of_cigarette_smoke_carcinogens. From there, you can easily read about the most common carcinogens present in cigarettes. If instead you want to read a more comprehensive list of substances present in cigarettes, check this other page: https://en.wikipedia.org/wiki/List_of_additives_in_cigarettes. According to World Health Organization, tobacco smoking is responsible for 5.4 million premature deaths worldwide in 2008, and 10 million smokers are predicted to die every year by 2025. The most common smoking-related causes of death are cardiovascular disease, chronic obstructive pulmonary disease, and various types of cancer, in particular lung cancer.
Let’s see more in details the consequences of smoking:
After being absorbed by lungs, poisons of smoking enter the blood circulation, and make blood thicker, increasing the risk of clot formation, blood pressure and heart rate (carbon monoxide and nicotine are responsible for this). These changes increase the chance of getting a heart attack or stroke.
Smokers have higher risk to develop stomach cancer or ulcers. Moreover, smoking can weaken the muscle that controls the lower end of the esophagus and allow acid reflux from the stomach back up to the gullet. Smoking is a significant risk factor for kidney cancer too.
Smoking weakens bones and reduces oxygen amount absorbed by the skin, determining faster aging. It increases risk of cancer in lips, tongue, throat and esophagus. More than 93% of oro-pharyngeal cancers are caused by smoking. Smoking can cause also impotence in men and infertility in women.
At last, the most (in)famous consequences of smoking occur to the lungs: it is responsible of pneumonia, emphysema and lung cancer. Smoking causes 84% of deaths from lung cancer and 83% of deaths from chronic obstructive pulmonary disease (COPD), which is characterized by chronic bronchitis and emphysema.
Here under you can see a summary of smoking-related diseases.
And if I stop smoking?
The risk of developing such diseases drops quickly when you quit smoking. Smokers who stop before their mid-30s have approximately the same life expectancy as people who never smoke. After 35 years of age, a person who stops smoking recovers 2–3 months of healthy life expectancy for every year of smoking avoided. Also the excess risk of heart attack drops by 50% after quitting cigarettes, together with risks of developing the aforementioned diseases. Immediate benefits occur to the skin, which restores the normal color, and to the pulmonary activity.
Genetics and smoking
Is there a correlation between DNA and smoking? Can my DNA say if I will become a smoker? In other words, can my DNA decide if I will become a smoker? An interesting study published by Belsky et al. in 2013 revealed that there is no correlation between DNA and smoking initiation, but there is a correlation between conversion of smoking initiation to heavy smoking, stronger nicotine dependence and failure in the cessation attempts. So, there is some correlation, but the decision of smoking is always a choice of the person. No excuses, people: quit smoking if you do, never start if you don’t!
References:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3084482/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2733016/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5490618/
https://jamanetwork.com/journals/jamapsychiatry/fullarticle/1672838
Trust in Science 