Smoking's Effect On Immune System Severe Years After Quitting, Study Finds

The study published earlier this week in the journal 'Nature' stated that smoking "decreases the body's ability to fight off infection immediately and over time", and may also increase the risk of chronic diseases involving inflammation, like rheumatoid arthritis and lupus.

The disclaimer 'smoking is injurious to health' appears on all cigarette packs to deter people. It is no secret that smoking causes great damage to the lungs and heart, along with other body parts that begin to gradually decay. According to the Centers for Disease Control and Prevention (CDC), besides cancer, smoking leads to heart disease, stroke, lung diseases, diabetes, and chronic obstructive pulmonary disease (COPD), which includes chronic bronchitis. It also makes one susceptible to tuberculosis, certain eye diseases, and problems of the immune system including rheumatoid arthritis. Now, a new study has found that even after a person has quit smoking, its after-effects can linger for years.

According to a CNN report, the study published earlier this week in the journal 'Nature' stated that smoking "decreases the body's ability to fight off infection immediately and over time", and may also increase the risk of chronic diseases involving inflammation, like rheumatoid arthritis and lupus.

The study's co-author Dr Violaine Saint-Andr -- specialist in computational biology at Institut Pasteur in Paris -- was quoted as saying, "Stop smoking as soon as possible. The key message of our study, especially to the youth, is that there seems to be a significant interest for long-term immunity to never start smoking."

During the study, researchers analysed blood samples over time of a group of 1,000 healthy people aged 20 to 69 years, divided equally between men and women. Per the report, they wanted to check how as many as 136 variables like lifestyle, socioeconomic issues, dietary habits, gender, age and genetics affected immune response. The blood samples taken from participants were exposed to E. coli bacteria and the flu virus. Then, the person's immune response was measured.

It was found that smoking, body mass index (BMI) and a "latent infection caused by the herpes virus" had the most impact; smoking created the "biggest change". The report stated that smoking had "nearly the same impact on immune response as important factors such as age or sex".

So, even when smokers quit -- while their immune response got better -- it did not fully recover for years, according to study co-author Dr Darragh Duffy, who was quoted as saying: "The good news is, it does begin to reset. It is never a good time to start smoking, but if you are a smoker, the best time to stop is now."

According to the World Health Organization (WHO), nearly 267 million adults (15 years and above) in India (29 per cent of all adults) are tobacco users, per the Global Adult Tobacco Survey India, 2016-17. The most prevalent form of tobacco use in our country is "smokeless tobacco". Commonly-used products are khaini, gutkha, betel quid with tobacco and zarda. Smoking forms of tobacco are bidi, cigarette and hookah.