New studies shed light on tobacco’s effects on lifespan and immune defenses – Liberation

The effects of cigarettes on health continue to be the subject of prolific research. A study published Feb. 8 in the journal NEJM estimates that the odds of reaching age 80 are about the same for nonsmokers who quit before age 40. It is enough to soothe the hearts of those for whom smoking was a temporary mistake of youth. Those who continue lose a dozen years of life compared to non-smokers.

“The key message is that smoking cessation is effective and quick, and that quitting at any age is beneficial,” insists on liberation Study author Prabhat Jha, an epidemiologist in Toronto. “At all ages and compared to smokers, quitting smoking for less than three years can help avoid five years of life lost. Quitting for more than ten years avoids ten years of life lost, giving a survival similar to that of never smokers.Researchers insist.

A very solid study is based on monitoring data of 1.48 million adults in four different countries (Canada, United Kingdom, United States, Norway). In this population, they compared mortality risk for less than three years, three to nine years, and more than ten years by comparing active smokers, nonsmokers, and ex-smokers. Surprisingly, smokers have an increased risk of respiratory, vascular diseases and cancer.

If Prabhat Jha’s study focuses only on mortality, this is not just the effect of cigarettes. “Smoking Persistently Modulates Adaptive Immunity”.So concluded another study published in the journal Wednesday, February 14 Nature. This work highlights a hitherto overlooked element: the adaptive immune system, which builds up over time with infection, remains impaired for years afterward.

These findings are based on a sample of one thousand people. These were selected more than ten years ago as part of a project led by the Pasteur Institute in Paris, and then their immunity was regularly studied through various tests, especially blood tests. This type of cohort observation makes it possible to assess how various factors influence health and metabolism over time. According to researchers led by biologist Violaine Saint-André, in the present case, it is smoking that stands out for its influence, more than other factors such as sleep time or degree of physical activity.

“Protect Your Long-Term Immunity”

We already know that smoking damages the proper functioning of the immune system. The study confirms this, finding that part of this effect disappears soon after smoking cessation. But, and this is the great innovation, it is not the same as a weakening of the adaptive immune system.

In some individuals, the effects persist for years, even decades, after smoking cessation, even if the sample is too small and the actions too variable to extrapolate a precise average duration.. “To preserve your long-term immune system, it’s probably better to never start smoking.”Summarized biologist Violaine Saint-André during a press conference.

While knowledge about the effects of smoking on the body is becoming more refined, the public health message remains the same: the best thing to do is not to smoke, or to stop as quickly as possible. According to the World Health Organization, tobacco kills about 8 million people worldwide every year.