Lack of evidence that obesity is a cause of pilonidal sinus disease

Objective: To find out whether pilonidal sinus is more common among obese p eople. Design: Retrospective study from hospital records. Setting: Two university hospitals, Turkey. Subjects: 419 patients who were operated on for pilonidal sinus disease; an d 213 age and sex matched patients with benign diseases other than pilonida l sinus disease and who were not morbidly obese acted as controls. Main outcome measures: Comparison of body mass index (BMI) in the two group s. Results: Patients with BMI of 25-30 were classified as overweight (61/419, 15% compared with 28/213, 13%), and those with BMI of 30 or more as obese ( 7/419 compared with 4/213, 2% in each group). Mean (SD) BMI of patients wit h pilonidal sinus disease was 26.0 (3.9) compared with 25.6 (3.9) in the co ntrol group (p = 0.4). Conclusion: Obesity alone is not an important factor in the aetiology of pi lonidal sinus disease.