You may want to stop smoking if you care about your immune system — here's why?

Smoking is so bad for the body that it alters a person's immune system, making them more susceptible to illness and infection even years after they have stopped, as per a recent study.

Smoking continues to be the greatest preventable cause of death in the United States, accounting for over 480,000 deaths annually, despite a decline in smoking rates since the 1960s, according to CNN.

Health professionals have warned smokers for many years that their habit can cause major issues such as lung cancer, heart attacks, and strokes, but a new study released on Wednesday in the journal Nature provides even more justification for giving up.

According to the research, smoking lowers the body's capacity to fight off infections both instantly and over time. It may also increase a person's risk of developing chronic inflammatory disorders like lupus and rheumatoid arthritis.

“Stop smoking as soon as possible,” warned study co-author Dr Violaine Saint-André, a specialist in computational biology at Institut Pasteur in Paris. “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.”

Blood samples from 1,000 healthy individuals between the ages of 20 and 69 were examined throughout time by the researchers. There was an equal distribution of males and women in the group.

The researchers sought to determine the effects of 136 factors on immunological response, including age, sex, genetics, lifestyle, and socioeconomic problems. They assessed the immune response after exposing the blood samples to common pathogens including the flu virus and E coli bacteria.

The three factors that had the biggest effects were body mass index, smoking, and a latent herpes virus infection. Smoking produced the biggest change. It affected the immunological response almost as much as significant variables like age or sex.