Recent Smoking Is a Risk Factor for Anal Abscess and Fistula

BACKGROUND: Smoking is a risk factor for inflammatory, fistulizing cutaneous diseases. It seems reasonable that smoking might be a risk factor for anal abscess/fistula. OBJECTIVE: This study aimed to test the hypothesis that recent smoking is a risk factor for development of anal abscess/fistula. DESIGN: This is a case-control study. SETTINGS: This study was conducted at a Department of Veterans Affairs general surgical clinic. PATIENTS: Included in the study were 931 patients visiting the general surgical clinic over a 6-month period. INTERVENTIONS: A tobacco use questionnaire was administered. MAIN OUTCOME MEASURES: Patients with anal abscess/fistula history were compared with controls, who had all other general surgical conditions. To investigate the temporal relation between smoking and the clinical onset of anal abscess/fistula, we compared the group consisting of current smokers and former smokers who had recently quit, against the group consisting of nonsmokers and former smokers who had quit a longer time ago (ie, not recently). We excluded patients with IBD and HIV. RESULTS: Cases and controls were comparable in age (57 and 59 y) and sex (93% and 97% male). After exclusions, there were 74 anal abscess/fistula cases and 816 controls. Among the anal abscess/fistula cases, 36 patients had smoked within 1 year before the onset of anal abscess/fistula symptoms, and 38 had not smoked within the prior year; among controls, 249 had smoked within 1 year before seeking surgical treatment, and 567 had not (OR 2.15, 95% CI 1.34-3.48, 2-tail P = .0025). Using a 5-year cutoff for recent smoking, the association was less pronounced but still significant (OR 1.72, 95% CI 1.03-2.86, P = .0375), and the association was insignificant at 10 years (OR 1.34, 95% CI 0.78-2.21, P = .313). LIMITATIONS: Limitations of the study included self-selection bias, recall bias, convenience sample, and noninvestigation of the dose-response relationship. CONCLUSIONS: Recent smoking is a risk factor for anal abscess/fistula development. As in other smoking-related diseases, the influence of smoking as a risk factor for anal abscess/fistula diminishes to baseline after 5 to 10 years of smoking cessation. Anal abscess/fistula can be added to the list of chronic, inflammatory cutaneous conditions associated with smoking.