Smoking Intensity, Duration, and Cessation, and the Risk of Rheumatoid Arthritis in Women

Cigarette smoking has been associated with rheumatoid arthritis (RA), but the importance of smoking intensity, duration, and time since quitting, and whether the risk is primarily for rheumatoid factor (RF) seropositive versus seronegative RA are still unclear. We conducted a prospective analysis of smoking and the risk of RA among 103,818 women in the Nurses’ Health Study. A total of 680 RA cases, diagnosed from 1976 and 2002, were confirmed using a questionnaire and medical record review. Sixty percent were RF positive. Cox proportional hazards models calculated the relative risks (RRs) of RA with smoking, adjusting for reproductive and lifestyle factors. The RR of RA was significantly elevated among current (RR 1.43 [95% confidence interval 1.16-1.75]) and past smokers (RR 1.47 [95% confidence interval 1.23-1.76]), compared with never smokers. The risk of RA was significantly elevated with 10 pack-years or more of smoking and increased linearly with increasing pack-years ( P trend