Another reason to quit: Smokers found to have stronger innate immune responses

Results from two new studies provide more fodder for physicians and other healthcare professionals encouraging their patients to quit smoking.One shows a different immune response in smokers compared to non-smokers that lingers after quitting, but eventually improves. The other suggests that stopping smoking at any age is associated with a longer life.Researchers from Institut Pasteur at Université Paris Cité used whole blood samples from 1,000 healthy volunteers to examine immune responses to environmental factors. They examined cytokine protein secretion when various pathogens were introduced to the blood samples. They measured cytokine secretions after introduction to pathogens that suggested innate immune stimulation (e.g, E. coli) and others that indicate of adaptive immune stimulation (e.g, anti-CD3 antibodies). Smoking impacted both innate and adaptive immune responses, with significantly higher responses than non-smokers. There was a strong correlation between the number of years smoking and the immune response. These differences in immune responses in smokers compared to non-smokers was similar to differences in immune responses seen in different ages, sex and genetic variations.These stronger immune responses could suggest more symptomatic disease and more susceptibility to infections than non-smokers, senior author Darragh Duffy said in a press briefing.The key message, particularly for young people, is “there seems to be a keen interest for long-term immunity to never start smoking,” said lead author Violaine Saint-Endré.Read: Want people to quit smoking? Cover the meds: CMAJ commentaryFormer smokers showed a persistent increase in adaptive immune response, but not innate immune response. Further analysis by the researchers showed that this continued effect on adaptive immune response is associated with DNA mutations in genes involved in metabolism regulators, among others. This finding stayed even when the researchers studied various genotypes.Yet even for those who already smoke, there are benefits to quitting. The innate immune response goes down to levels similar to those seen in non-smokers, and over time, the adaptive immune response does eventually lower, Duffy confirmed.Read: Nova Scotia announces its first screening program for lung cancerThe benefits of quitting smoking were even more obvious in a study by researchers from Toronto and Norway. The pooled analysis of large cohorts in the U.S., Canada, U.K. and Norway showed former smokers who had quit smoking for 10 years or more had a risk of death similar to those who had never smoked. The researchers concluded that quitting smoking at any age is associated a lower risk of death overall, and from vascular, respiratory and neoplastic diseases, compared to those who continued to smoke. The risk of death decreased as early as three years after smoking cessation. After three years, former smokers had a 1.3-fold higher risk of death compared to never smokers, as opposed to the three-fold higher risk of death that current smokers have compared to never-smokers. The study results suggested that quitting at a younger age brings greater benefits. Those who quit before 40 years of age had a lower excess risk of death compared to smokers who quit at an older age."Quitting smoking is ridiculously effective in reducing the risk of death, and people can reap those rewards remarkably quickly," said Dr. Prabhat Jha in a press release. Dr. Jha was the lead researcher and is a professor at University of Toronto’s Dalla Lana School of Public Health and Temerty Faculty of Medicine, and executive director of the Centre for Global Health Research at Unity Health Toronto.“Many people think it’s too late to quit smoking, especially in middle age,” Dr. Jha said. “But these results counter that line of thought. It’s never too late, the impact is fast and you can reduce risk across major diseases, meaning a longer and better quality of life.”Physicians and other healthcare professionals can encourage smoking cessation whenever a patient interacts with the healthcare system, Dr. Jha said. “This can be done with concern, and without judgement or stigma, recognizing that cigarettes are engineered to be highly addictive.”The study results can be found in Nature and the NEJM EvidenceRead: Clinical trial examines the efficacy of e-cigarettes for smoking cessation

Another reason to quit: Smokers found to have stronger innate immune responses

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