A recent study has revealed that smoking tobacco not only poses immediate health risks but also induces long-lasting changes in the immune system, rendering individuals more susceptible to diseases and infections even years after quitting.
Despite declining smoking rates since the 1960s, it remains the leading cause of preventable death in the United States, claiming over 480,000 lives annually.
While the well-known risks of smoking include conditions like lung cancer, heart attacks, and strokes, a study published in the journal Nature on Wednesday presents a new incentive for smokers to quit.
The research underscores how smoking diminishes the body’s ability to combat infections both in the short term and over extended periods.
It also suggests that smoking may increase the risk of chronic inflammatory diseases such as rheumatoid arthritis and lupus.
“Stop smoking as soon as possible,” cautioned Dr. Violaine Saint-André, a computational biology specialist at Institut Pasteur in Paris and co-author of the study.
“Our study’s key message, particularly for young people, is that there appears to be significant long-term implications for immunity if you never start smoking.”
Examining blood samples from a diverse group of 1,000 healthy individuals aged 20 to 69, the researchers assessed 136 variables, including lifestyle, socioeconomic factors, dietary habits, age, sex, and genetics, to evaluate their impact on immune response.
Samples were exposed to common pathogens like E. coli bacteria and the flu virus to measure immune reactions.
Of all the variables studied, smoking, body mass index (BMI), and latent herpes virus infections showed the most significant impacts, with smoking exerting a nearly equivalent influence on immune response as factors like age or sex.
“The effect is substantial,” noted Saint-André.
Although quitting smoking showed some improvement in immune response levels in participants, complete recovery took years, explained Dr. Darragh Duffy, leader of the Translational Immunology unit at Institut Pasteur and study co-author.
“The positive news is that the immune system does begin to reset,” Duffy emphasized. “While there’s never a good time to start smoking, the best time to quit is now.”
The study also highlighted that heavier smoking correlated with more pronounced alterations in immune response.
“Reducing smoking, regardless of the amount, still confers benefits in terms of mitigating these effects,” Duffy added.
Furthermore, the research uncovered that smoking induces lasting epigenetic changes in the immune system, affecting both innate and adaptive immunity.
While the impact on innate immunity subsides quickly after smoking cessation, alterations in adaptive immunity persist even after quitting.
“In our study, the significant finding was that smoking affects adaptive immunity, particularly B cells and regulatory T cells, through epigenetic modifications,” Saint-André elaborated.
The study’s findings are based on lab tests with blood samples, which may not fully replicate real-life immune responses.
However, the study’s comprehensive analysis of a large sample set provides robust insights into the effects observed.
Dr. Yasmin Thanavala, a professor at the Roswell Park Cancer Institute specializing in immune response research related to smoking, praised the study as a validation of her own research with mice exposed to smoke. She noted that while lung changes may diminish, they do not completely disappear.
She pointed out a limitation in the study—the homogeneity of the French participants, all with lower body weights—calling for future research to include broader demographic considerations.
Dr. Albert Rizzo, Chief Medical Officer of the American Medical Association, highlighted the study’s contribution in explaining the underlying mechanisms behind smoking-related immune dysfunction, beyond lung inflammation alone.
“This study affirms what we’ve long suspected, providing insights into the ‘why’ behind these health issues,” remarked Rizzo, who was not involved in the study.
The study underscores the imperative for smoking cessation not only to prevent immediate health risks but also to safeguard long-term immune function and health.
