Current smoking and >10 pack-years of smoking have demonstrated a strong and specific association with an increased risk for occurrence of anti-double-stranded DNA (dsDNA+) systemic lupus erythematosus (SLE), according to a recent prospective cohort study published in Annals of the Rheumatic Diseases.
The Nurses’ Health Study (NHS) enrolled a total of 121,701 US female nurses in 1976; the NHSII study enrolled 116,430 nurses in 1989. Lifestyle, environmental, and medical data were compiled via the use of biennial questionnaires. Incident SLE was verified by review of medical records.
Of 286 patients with SLE who were identified (159 in NHS [1978-2012] and 127 in NHSII [1991-2013], mean age was 49.2±10.3 years. Overall, 42% of these patients were dsDNA+ when diagnosed with SLE.
Compared with never-smokers, current smokers had an increased risk for dsDNA+ SLE (hazard ratio [HR], 1.86; 95% CI, 1.14-3.04), but prior smokers did not (HR, 1.31; 95% CI, 0.85-2.00). Women who smoked >10 pack-years had an increased risk for dsDNA+ SLE vs never-smokers (HR, 1.60; 95% CI, 1.04-2.45). No associations were observed between smoking status or pack-years and overall SLE or dsDNA– SLE.
The findings of this study demonstrate a strong and specific association between current smoking and risk for dsDNA+ SLE, which is a severe subtype of SLE. Although future studies may be able to evaluate the association between smoking and SLE with individual autoantibodies, this may be challenging, as the 2 are highly reciprocal. Smoking cessation reduced the risk for dsDNA+ SLE to the level of nonsmokers at 5 years, which implies that dsDNA+ and risk for SLE are modifiable.
Barbhaiya M, Tedeschi SK, Lu B, et al. Cigarette smoking and the risk of systemic lupus erythematosus, overall and by anti-double stranded DNA antibody subtype, in the Nurses’ Health Study cohorts [published online October 7, 2017]. Ann Rheum Dis. doi:10.1136/annrheumdis-2017-211675