title: Effect of body mass index on groin hernia surgery.
abstract: OBJECTIVE
  To analyze the effect of underweight, overweight, and obesity in relation to clinical characteristics, the risk of postoperative complications, 30-day mortality, and reoperations for recurrence after groin hernia surgery.
  
  
  BACKGROUND
  Groin hernia surgery is one of the most frequent operations performed in general surgery. Several studies have demonstrated a protective effect of overweight and obesity on the risk of developing primary groin hernia. However, obesity has also been suggested to increase the risk for recurrence of groin hernia.
  
  
  METHODS
  Through the Swedish Hernia Register, 49,094 primary groin hernia operations were identified between January 1, 2003 and December 31, 2007. Patients were divided into 4 body mass index (BMI) groups: BMI 1, <20 kg/m2; BMI 2, 20 to 25 kg/m2; BMI 3, 25-30 kg/m2; and BMI 4, >30 kg/m2.
  
  
  RESULTS
  Of the 49,094 patients, 3.5% had a BMI <20 kg/m2 and 5.2% were obese. Altogether, women constituted only 7.7% of the studied group, but among patients with BMI <20 kg/m2 that had surgical procedures for femoral hernia, 81.4% were women. The relation between BMI and postoperative complications was U-shaped and after adjustment for age, gender, and emergency procedure, patients with BMI <20 and >25 had a significant increased risk when compared with patients with BMI from 20 to 25. Reoperation for recurrence of groin hernia has an increased hazard ratio of 1.20 (95% confidence interval, 1.00-1.40) in overweight, which was particularly evident after open suture and preperitoneal mesh techniques.
  
  
  CONCLUSIONS
  In this large and unselected population of patients with a first surgical procedure for groin hernia a relative dominance of female and femoral hernias presented as an emergency condition was observed in the low BMI group. The prevalence of obesity was markedly low. Both lean and obese patients had an increased risk for postoperative complications.
authors.affiliation: Department of Surgery, Sahlgrenska University Hospital/Ostra, Göteborg, Sweden. anders.rosemar@vgregion.se
authors.forename: Anders
authors.initials: A
authors.lastname: Rosemar
authors.forename: Ulf
authors.initials: U
authors.lastname: Angerås
authors.forename: Annika
authors.initials: A
authors.lastname: Rosengren
authors.forename: Pär
authors.initials: P
authors.lastname: Nordin
mesh_terms: D015992:Body Mass Index; D016009:Chi-Square Distribution; D005260:Female; D006552:Hernia, Inguinal / Q000601:surgery*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000453:epidemiology; D016016:Proportional Hazards Models; D012008:Recurrence; D012042:Registries; D012086:Reoperation; D012307:Risk Factors; D013548:Sweden / Q000453:epidemiology; D016896:Treatment Outcome