Study finds potential long-term effects on the immune system from smoking

Despite a decline in smoking rates globally, it remains the leading cause of preventable death in many countries. Traditionally, healthcare providers have warned smokers about the serious health risks associated with the habit, such as lung cancer, heart attacks, and strokes. However, a study published in Nature highlights another reason to kick the habit.

The study has found that smoking tobacco can leave people more susceptible to disease and infection even long after they have quit. This is because smoking reduces the body’s ability to combat infections both immediately and over time, potentially increasing the risk of chronic inflammatory diseases like rheumatoid arthritis and lupus.

Examining blood samples from 1,000 healthy people aged 20 to 69, the researchers analyzed various factors, including lifestyle, socioeconomic status, dietary habits, age, sex, and genetics, to assess their impact on immune response. They exposed the blood samples to common pathogens like E. coli bacteria and the flu virus to gauge immune response.

Among the variables studied, smoking, body mass index, and latent herpes virus infection exerted the most significant influence, with smoking demonstrating the most pronounced effect. Interestingly, the study found that the extent of smoking correlated with the magnitude of immune response alteration.

The researchers explain that smoking has long-term epigenetic effects on the body’s immune system, particularly on its innate and adaptive responses. While the impact on the innate response diminishes shortly after quitting smoking, the effect on the adaptive response persists even after cessation.

The innate immune response involves the body’s general defenses, including the skin, mucous membranes, immune cells, and proteins, which provide rapid but unspecific defense against pathogens. When deemed insufficient, the adaptive immune system, comprising antibodies and lymphocytes, kicks in, offering targeted defense against previously encountered threats.

Study co-author Dr. Darragh Duffy noted: “The good news is, it does begin to reset. “It’s never a good time to start smoking, but if you’re a smoker, the best time to stop is now. Cutting down any amount is still a good thing in terms of this impact.”