Risk factors associated with inguinal hernias: a case control study

Abstract

Objectives: To assess reported risk factors for the development of inguinal hernias, to develop a method of quantifying physical effort, and to correlate them.

Design: Case control study.

Setting: District hospital, Valencia, Spain.

Subjects: 290 selected patients who had undergone inguinal hernia repair, and 290 age and sex matched controls.

Interventions: Each patient was interviewed and data collected on a specially designed questionnaire, and an "effort score" calculated.

Main outcome measures: Incidence of specified risk factors.

Results: The only significant risk factor was physical effort (lifting heavy objects repeatedly over long periods of time), relative risk 2.92, 95% confidence interval 2.11 to 4.04. In addition, there were significant differences between index cases and controls in standard of education (p < 0.001), consumption of alcohol (p = 0.02), chronic cough (p < 0.001), net monthly income (p = 0.04), and amount of physical effort expended (p < 0.001). Patients with indirect hernias expended significantly more physical effort and were both heavier and taller, and patients with femoral hernias waited significantly longer than the others before having their hernias repaired.

Conclusion: Inguinal hernias are associated with the expenditure of a considerable amount of physical effort, and are commoner among younger, poorly educated manual workers.