Childhood parental smoking may have a direct impact on adult-onset rheumatoid arthritis (RA) in women, according to study results published in Arthritis & Rheumatology.
Researchers analyzed biennial questionnaire data from the Nurses’ Health Study II prospective cohort to assess the impact of maternal smoking during pregnancy, childhood parental smoking, and years lived with a smoker from the age of 18 years. Medical record review determined incident RA serostatus, and the controlled direct effect of each passive exposure was estimated. Researchers adjusted for early-life and time-updated adult factors, including personal smoking.
A total of 532 incident RA cases – 66% seropositive – were identified among 90,923 women during a median follow-up of 27.7 years. After adjustment for confounders, RA was found to be associated with maternal smoking during pregnancy (hazard ratio [HR], 1.25; 95% CI, 1.03-1.52). However, the association was not present with the inclusion of subsequent personal smoking.
Childhood parental smoking was associated with seropositive incident RA, after adjustment for confounders (HR, 1.41; 95% CI, 1.08-1.83). After controlling for adult personal smoking, the researchers noted an association between seropositive RA and childhood parental smoking (HR, 1.75; 95% CI, 1.03-2.98).
In a stratified analysis, there was no increased risk for RA among lifelong never personal smokers. However, there was a statistically significant increased risk among ever smokers (HR, 2.18; 95% CI, 1.23-3.88). Further, there were no significant associations between adult passive smoking and RA.
The study was limited by the inability to study early-life RA, potential associations between longer durations of passive smoke exposure and risk, selection and recall bias from postexposure enrollment, and the use of medical record review to determine serostatus of RA.
Researchers concluded, “Our observations are most compatible with the ‘cumulative exposure’ model in life-course epidemiology, in which both childhood parental smoking and later-life personal smoking increase the risk of adult incident seropositive RA.”
Disclosure: Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of disclosures.
Yoshida K, Wang J, Malspeis S, et al. Passive smoking throughout the life course and the risk of incident rheumatoid arthritis in adulthood among women. Arthritis Rheumatol. Published online August 18, 2021. doi:10.1002/art.41939