Childhood Secondhand Smoke Exposure Linked to Future Rheumatoid Arthritis Risk

Childhood exposure to secondhand smoke may heighten the risk of developing rheumatoid arthritis (RA) later in life, even in non-smokers, according to new research.

RA, the most common type of arthritis, is believed to be triggered by a mix of environmental and genetic factors. Although tobacco exposure is known to be a contributing environmental factor to increased RA risk, limited data exist on the role of secondhand smoke in triggering the disease.

The study, published in the journal Rheumatology, investigated the potential association between smoking status, including secondhand exposure during childhood and adulthood, and the risk of RA.

To determine the link between smoking status and RA risk, the researchers examined data on 98,995 French women prospectively followed since 1990. Patients responded to self-administered questionnaires every 2 to 3 years, reporting on medical events and general, lifestyle, and environmental characteristics. The researchers collected arthritis diagnoses in 3 successive questionnaires and confirmed whether women received an arthritis-specific medication.

Among 71,248 women, the researchers confirmed 371 incident RA cases, according to the findings. In patients who had never smoked, secondhand exposure during childhood was associated with a borderline increased risk of RA in the same range as active smoking in adults, according to the study. Active smokers who were exposed to secondhand smoke during childhood had a greater risk of RA and experienced earlier onset of the disease compared with active smokers who were not exposed.

“Further study is needed to explore if this increased risk is also mainly observed in people carrying the gene at risk for rheumatoid arthritis, which is quite likely with regard to tobacco,” lead author Dr Marie-Christine Boutron-Ruault said in a statement.

The study findings suggest for the first time that additional exposure to tobacco early in life, even in non-smokers, increases the risk of RA and may lead to earlier onset of the disease. The researchers suggested that avoiding passive tobacco exposure in childhood can play a role in preventing the development of RA in the future.

“As demonstrated for many other risks, our results highlight the importance of protecting children from any environmental tobacco smoke exposure, especially in those with a family history of RA,” the researchers concluded.

References

Seror R, Henry J, Gusto G, et al. Passive smoking in childhood increases risk of developing rheumatoid arthritis. Rheumatology. 2018. https://doi.org/10.1093/rheumatology/key219

Secondhand smoke increases risk of children developing arthritis later in life [news release]. Oxford University Press. https://www.eurekalert.org/pub_releases/2018-08/oupu-ssi080918.php. Accessed August 15, 2018.