Passive smoking during childhood has been linked to an increased risk for rheumatoid arthritis (RA), according to a study recently published in Rheumatology. This risk is likely to affect future nonsmokers and light smokers alike.

This study drew from 98,995 female participants in the French E3N cohort, of whom 71,248 were analyzed for this study. There were 371 cases of incident RA among the cohort. The risk for RA was higher among ever-smokers with no exposure to passive smoking during childhood (hazard ratio [HR], 1.38; 95% CI, 1.10-1.74). Childhood exposure to passive smoking was associated with a marginally larger risk for RA than active adulthood smoking (HR, 1.43; 95% CI, 0.97-2.11). Childhood passive smoking was also associated with a higher risk for RA in ever-smokers, compared with ever-smokers with no exposure to childhood passive smoking (HR, 1.67; 95% CI, 1.17-2.39), but this difference was not significant (P =.30). However, smokers with childhood passive smoking exposure presented with earlier onset of RA.

The female volunteers in the French E3N cohort were followed since 1990, and data on medical events and various characteristics were collected through self-administered questionnaires sent every few years. Diagnoses of RA were gathered in 3 consecutive questionnaires, and the receipt of a medication specifically for RA served to confirm the diagnosis. A Cox model adjusted for age was used to estimate participants’ risk for incident RA, with smoker status used as a time-dependent variable.

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The study researchers conclude that “active smoking is associated with an increased risk of RA. It suggests for the first time that passive exposure to tobacco during childhood might also increase the risk of RA in future light smokers and probably [nonsmokers]. Our results highlight the importance of avoiding any tobacco environment in children, especially in those with a family history of RA.”

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Reference

Seror R, Henry J, Gusto G, Aubin HJ, Boutron-Ruault MC, Mariette X. Passive smoking in childhood increases the risk of developing rheumatoid arthritis [published online August 14, 2018]. Rheumatology. doi:10.1093/rheumatology/key219