CHICAGO – Risk for seropositive rheumatoid arthritis among women declined substantially after smoking cessation, although increased risk for the disease persisted for up to 30 years after cessation, according to findings from a large prospective study presented at the ACR/ARHP 2018 Annual Meeting.
“Compared to never smoking, past and current smoking are both associated with increased risk [for] seropositive RA,” the researchers wrote. “Thus, smoking cessation may delay or even prevent RA, but previous investigations were limited for definitive conclusions by short follow-up. ... We investigated the impact and timing of smoking cessation on RA risk using two large prospective cohorts with lengthy follow-up.”
Xinyi Liu, a member of the rheumatology, immunology and allergy research group in the department of medicine at Brigham and Women’s Hospital, and colleagues used the Nurses’ Health Study (1976-2014) and the Nurses’ Health Study II (1989-2015) to examine smoking cessation and risk for RA. The analysis included 230,732 women. The mean age in 1988 was 54.3 years (standard deviation, 7.2); 18.8% of women were current smokers and 36% were former smokers. In 1989, the mean age was 34.4 years (standard deviation, 4.7); 13% were current smokers and 21% were former smokers.
Data on smoking exposure, as well as covariates, were gathered prospectively with biennial surveys. The presence of RA was self-reported by women and a review of medical records established RA according to ACR criteria. The researchers confirmed the serologic presence of RA using rheumatoid factor and/or anticyclic citrullinated peptide according to chart review.
Over 6,037,151 person-years of follow-up, the researchers observed 1,528 incident cases of RA. The majority of these cases (n = 969) were seropositive; 559 were seronegative. Current smoking elevated the risk for seropositive RA (multivariable HR, 1.67; 95% CI, 1.38-2.01) but not seronegative RA (HR, 1.20; 95% CI, 0.93-1.55).
A slightly increased risk for seropositive RA remained demonstrable 30 years after smoking cessation when compared with never smoking (multivariable HR, 1.30; 95% CI, 1.01-1.68), although the risk for seropositive RA continued to decline over time among former smokers when compared with individuals who quit more recently (within 0 to 2 years). In the subgroup of former smokers, the researchers observed a linear relationship between years since smoking cessation and decreased risk for seropositive RA (P = .002) but not for seronegative RA (P = .78). The HR among individuals who stopped smoking more than 30 years ago was 0.63 (95% CI, 0.44-0.90) for seropositive RA when compared with individuals who stopped smoking less than 5 years ago.
“In this large prospective study with up to 38 years of follow-up, past smokers had significantly reduced risk for seropositive RA after quitting smoking, although residual elevated risk for RA remained even 30 years after quitting compared to never-smokers,” the researchers wrote. “These results provide evidence that sustained smoking cessation reduces RA risk.” - by Julia Ernst, MS
Liu X, et al. Abstract 1909. Presented at: 2018 ACR/ARHP Annual Meeting, Oct. 20-24, 2018; Chicago.
Disclosures: Liu reports no relevant financial disclosures. Please see the abstract for all other authors’ relevant financial disclosures.