Jeffrey A. Sparks
Individuals who have quit smoking for a sustained period of time — 30 or more years — have a 37% reduced risk for seropositive rheumatoid arthritis, compared with those who quit between 0 and 5 years ago, according to data published in Arthritis Care & Research.
“Previous studies have established smoking as a risk factor for RA, but mostly compared current or past smokers to never smokers,” Jeffrey A. Sparks, MD, MMSc, of Brigham and Women’s Hospital, told Healio Rheumatology. “We were interested to investigate how the behavior change of quitting smoking may affect RA risk.”
To determine the impact of smoking cessation, and well as the timing of cessation, on RA and serologic phenotypes, Sparks and colleagues studied data from the Nurses’ Health Study and the Nurses’ Health Study II. Sparks and colleagues excluded participants with RA and other connective tissue diseases at baseline, as well as those with missing smoking or follow-up information. The researchers included 117,182 from the original cohort and 113,550 from the Nurses’ Health Study II. They then used Cox regression to determine HRs for seropositive and seronegative RA based on smoking status, intensity, pack-years and years since cessation.
Individuals who have quit smoking for a sustained period of time — 30 or more years — have a 37% reduced risk for seropositive RA, compared with those who quit between 0 and 5 years ago, according to data.
According to the researchers, 1,528 of the participants in the final analysis developed RA, including 969 who were seropositive, during 6,037,151 personyears of followup. Compared with never smoking, current smoking increased the risk for all RA (HR = 1.47; 95% CI, 1.271.72) as well as seropositive RA (HR = 1.67; 95% CI, 1.382.01). However, there was little evidence suggesting a link between smoking and the risk for seronegative RA (HR = 1.2; 95% CI, 0.931.55).
“We found differences in smoking for the risk of seropositive RA and seronegative RA, suggesting these might be separate entities even though both have a similar clinical presentation,” Sparks said. “These findings provide further evidence to counsel patients who are at elevated RA risk to quit smoking.”
In addition, increased smoking pack-years was associated with an increased risk for all RA (P < .0001), including seropositive RA (P < .0001). Increasing the duration of smoking cessation was associated with a decreased risk for all RA (P = .009), including seropositive RA (P =0.002). Compared with participants who had quit less than 5 years ago, those who quit more than 30 years ago demonstrated a reduced risk for seropositive RA (HR = 0.63; 95% CI, 0.440.9).
However, those who had quit for more than 30 years still carried a modestly elevated risk for all RA (HR = 1.25; 95% CI, 1.021.53) and seropositive RA (HR = 1.3; 95% CI, 1.011.68) compared with those who never smoked.
“We found that risk for seropositive RA declined steadily after sustained smoking cessation,” Sparks said. “Ours is one of the first to show that a behavior change may actually modify RA risk. This means that quitting smoking could delay or even prevent seropositive RA.”– by Jason Laday
Disclosure: The researchers report grant support from the NIH. Please see the study for all other relevant financial disclosures.