Originally published by 2 Minute Medicine® (view original article). Reused on AccessMedicine with permission.

1. Cigarette smoking was associated with increased risk of antineutrophil cytoplasmic antibody associated-vasculitis.

Evidence Rating: 3 (Average)

Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) confers high mortality and morbidity for affected patients and likely has a multifactorial etiology. While contribution from environmental factors have been previously documented, the association between cigarette smoking and risk of AAV is unclear. To address this knowledge gap, researchers conducted a large case-control study with a cohort of 484 patients diagnosed with AAV between 2002 to 2017, and matched with 3 randomly-selected controls based on sex, race, and age to determine the possible associations between smoking status and AAV development. Ultimately, 473 cases of AAV were matched with 1419 controls, and it was found that patients with AAV were more likely to be former (OR, 1.6; 95% CI, 1.3-2.0) or current smokers (OR, 2.7; 95% CI, 1.8-4.1), with a dose-dependent relationship between risk and pack-years of exposure (P<.001). Likewise, there was a significantly greater proportion of current or former smokers among participants with AAV (54%) than controls (42%), with an increased odds ratio of having AAV in smokers versus controls (OR, 1.7, 95% CI, 1.4-2.2). The strongest associations were found among patients with MPO-ANCA-positive disease, and weaker associations were found in patients with PR3-ANCA-positive AAV. This study represents the first large scale study investigating the association between cigarette smoking and AAV, and provides evidence to suggest smoking as a modifiable risk factor for the potential development of AAV. While pathogenic mechanisms should be further explored to provide potential therapeutic targets, this study emphasizes yet another reason for why clinicians should strongly counsel against cigarette smoking in patients.

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