Quitting smoking reduces mortality, despite weight gain
A study shows that quitting smoking halves the risk of premature mortality, regardless of the excess weight accumulated by most ex-smokers.
Smokers are generally thinner than non-smokers because of the multiple effects of nicotine on metabolism (reduced appetite, inhibition of certain enzymes involved in fat assimilation, increased basal body energy expenditure).
These metabolic impacts also largely explain why people who quit smoking put on weight in the months following cessation: 80% of ex-smokers gain 3 to 4 kilos after their last cigarette, an accumulation that can even exceed 10 kilos for some. It has also been observed that smoking cessation was associated with remarkable changes in the composition of the intestinal microbiome, with the appearance of a bacterial profile similar to that found in obese people.
It therefore seems that smoking cessation favours the development of a bacterial flora that is better able to extract energy from food, which could contribute to the weight gain of ex-smokers.
Given the many negative health effects of excess fat (hyperglycaemia, chronic inflammation), is it possible that these disturbances could reduce the many well-documented health benefits of quitting smoking? To answer this question, a team of Australian researchers followed a population of 16,663 smokers (21.5%), ex-smokers (31.4%) and never smokers (47.1%) for a period of 8 years. Throughout the study, the researchers questioned the participants at regular intervals about their health status, and deaths that occurred during this period were compiled from a national register.
The study first confirmed that the ex-smokers had a much greater weight gain than regular smokers, with an average accumulation of 3.14 kg. This excess fat, however, did not appear to influence the important benefits that are associated with quitting smoking on the risk of premature mortality.
Compared to those who continued to smoke, all ex-smokers had a halved risk of mortality, irrespective of the number of extra kilograms accumulated following smoking cessation. No significant increase in the risk of cardiovascular disease, type 2 diabetes, cancer or chronic obstructive pulmonary disease (COPD risk) was also observed in ex-smokers with weight gain compared to those who had maintained a normal weight.
The reductions in risk of chronic disease and mortality associated with smoking cessation are so large that they far outweigh the negative impact of metabolic disturbances caused by excess fat.
Quitting smoking is difficult, but new ways have emerged in recent years that significantly increase the likelihood of success.
Currently, the most effective approach seems to be the use of electronic cigarettes, devices that vaporise nicotine at a low temperature and thus avoid inhaling the thousands of toxic carcinogenic compounds generated during tobacco combustion. The nicotine absorbed with these electronic cigarettes thus allows the smoker to satisfy his addiction, while being much less harmful to health(3).
Recent studies also show that these devices are about twice as effective as traditional approaches (gum, patch) for quitting smoking, especially among heavy smokers who have tried everything but simply cannot quit.
For example, a recent study shows that among these highly addicted smokers, the use of electronic cigarettes is associated with a six-month abstinence rate six times higher than that achieved with patches or gum (19 vs. 3%). These products can therefore represent a very interesting alternative for heavy smokers and allow them to enjoy the enormous benefits of quitting smoking on life expectancy. Even if it is at the cost of a few extra kilos, which can be lost afterwards!