June 9, 2021 — Secondhand smoke appears linked to a higher risk of rheumatoid arthritis in those who were exposed to it during childhood and adulthood, according to a new study. Though rheumatoid arthritis is not a common disease, the findings may be particularly relevant for those already at increased risk due to family history, according to the study’s lead researcher, Yann Nguyen, MD.
“Smoking is a risk factor of many diseases, including rheumatoid arthritis,” Nguyen tells WebMD. His findings, presented online June 2 at the annual European Alliance of Associations for Rheumatology (EULAR) meeting, suggest that “secondhand smoking, in childhood or in adulthood, also increases the risk of rheumatoid arthritis, and could trigger the disease at a younger age.”
Secondhand smoke has already been linked with several lung diseases and cancers, adds Nguyen, of the University of Paris-Saclay in Villejuif and
at Hospital Beaujon at the University of Paris in Clichy.
“We believe that it should be avoided as much as possible, especially among people who have an increased risk of rheumatoid arthritis, such as relatives of patients with rheumatoid arthritis,” Nguyen says.
The researchers relied on a French prospective cohort study designed to examine a/the possible link between environmental factors and chronic disease.
The study began to track 98,995 healthy French women in 1990. Most were about 49 years old.
A total of 698 women developed rheumatoid arthritis at an average 12 years after the study began.
The scientists defined exposure to secondhand smoke in childhood as spending several hours a day in a smoky room.
Secondhand smoke exposure in adulthood was defined as spending at least 1 hour per day around actively smoking adults.
About 1 in 7 of the women (13.5%) reported exposure to cigarette smoke as children, and just over half (53.6%) reported being exposed to smoking as adults. An overall 58.9% had secondhand exposure in adulthood or childhood, and 8.25% had both.
After taking into account differences between the women’s body mass index (BMI) and educational level, risk of rheumatoid arthritis was 1.4 times greater for women who never smoked but had childhood secondhand smoke exposure. Their risk was 1.3 times greater for women who never smoked but reported regularly being around secondhand smoke as adults.