Rédaction Africa Links 24 with Elizabeth Cooney
Published on 2024-02-14 16:00:52
The longstanding public health message to quit smoking or not start if you don’t smoke has been emphasized for decades. However, a recent study suggests that smoking is even more detrimental to health than previously thought.
The study, published in Nature, reinforces the importance of never starting to smoke, revealing that smoking has a longer-lasting negative impact on immune responses than previously understood. Researchers found that while people who quit smoking were able to recover normal function of their immune system’s ability to mount fast and general innate responses to bacteria or viruses, the slower, more targeted adaptive T cell defenses remembered from past pathogens did not return as quickly after quitting smoke.
The study was a part of the Milieu Intérieur project, a long-term study conducted in France to examine the effect of environmental factors on immune responses. A total of 1,000 participants answered questionnaires and underwent laboratory tests to stimulate production of 13 cytokines, which are molecules involved in immune defense, in response to 12 proteins active in microbial and viral infections. The results indicated that smoking, body mass index, and infection with cytomegalovirus were the three primary factors influencing variations in immune responses.
People who smoked showed increased inflammatory responses, and while these levels decreased after smoking cessation, the effects on adaptive responses persisted for many years after quitting. The study was considered “revelatory” by William Schaffner, a clinician, epidemiologist, and professor of infectious diseases at Vanderbilt University Medical Center. He highlighted that smokers are likely to be at an increased risk due to their adaptive immune response.
The researchers attributed the adverse effects of smoking to epigenetic changes, specifically methylation which modifies DNA sequences, affecting the activation or deactivation of certain genes. Through these modifications, smoking lowered DNA methylation, impacting the cytokines’ response to immune challenges.
The researchers plan to follow the same cohort for an extended period, particularly observing how healthy participants during the study are affected in the context of the Covid-19 pandemic. Clinical observations support these laboratory findings, and the study emphasizes the importance of vaccination to provide as much protection as possible in light of the impaired immune response in individuals who smoke.
The study concludes with a message to avoid smoking as much as possible, with a recommendation that if an individual is a smoker, the best time to quit is now. This new study emphasizes that smoking can have long-term consequences, through epigenetic modifications, and can significantly affect the immune responses of exposed individuals.
It is evident that environmental factors like smoking can have a substantial impact on health, underscoring the importance of creating awareness about the consequences of smoking and advocating for healthy lifestyle choices.
