Smoking is so damaging to the body that it alters a person's immune system, leaving them vulnerable to more diseases and infections even years after they've quit, a new study has found.
Although smoking rates have declined since the 1960s, it is still the leading cause of preventable death in the United States, causing more than 480,000 deaths each year.
For decades, health care providers have told smokers that the habit can lead to serious problems like lung cancer, heart attack or stroke, but a study published Wednesday in the journal Nature offers another reason to. quit smoking
Research shows how smoking lowers the body's ability to fight infection both immediately and over time, and can also put someone at risk of chronic diseases that involve inflammation, such as rheumatoid arthritis and lupus.
"Stop smoking as soon as possible," warned study co-author Dr. Violaine Saint-André, a specialist in computational biology at the Institut Pasteur in Paris. "The main message of our study, especially for young people, is that there seems to be a great interest in long-term immunity from never starting to smoke."
The researchers looked at blood samples from a group of 1,000 healthy people aged 20 to 69 over time. The group was split equally between men and women.
The researchers wanted to see how 136 variables including lifestyle, socioeconomic issues and dietary habits – in addition to age, sex and genetics – affected the immune response. They exposed blood samples to common microbes such as E. coli bacteria and the flu virus and measured the immune response.
Smoking, body mass index and a latent herpes virus infection had the greatest impact, with smoking making the biggest difference. It had almost the same influence on the immune response as important factors such as age or sex.