Relationship between hiatal hernia and inguinal hernia.

Several theories explain the development of hiatal hernia (HH). Since inguinal hernia (IH) is due to abdominal wall herniation, we hypothesized that if HH is caused by an excessive "push" from increased intraabdominal pressure, there would be a greater than chance association between HH and IH. The aim of this prospective case-control study was to determine the relationship between HH, identified at endoscopy, and IH, found on clinical examination. Outpatients, who were referred for elective upper GI endoscopy at the Endoscopic Unit, from January 1999 to December 1999, were evaluated. Data were collected regarding gender, age, BMI, presence or absence of HH, length of HH, and presence of IH on detailed abdominal examination of each subject. Five hundred fifty-nine outpatients were enrolled in this study. Of these, 128 (23%) had HH, whereas 431 (77%) patients did not. The average length of the HH was 2.7 +/- 0.9 cm (range, 1.5-6 cm). The overall risk of IH in patients with HH is 2.5-fold compared to those without HH (OR = 2.59). Obesity (BM, >25) was an additional risk factor for IH in patients with HH compared with normal weight (BMI, 21-25) (P < 0.05). Males with HH were more likely to have IH than females (OR = 2.86; 95% CI = 1.35-6.08). Inguinal and hiatal hernias occur together more often than expected by chance alone. Male gender and obesity increase the risk of association. These results suggest that a common etiology may exist for both IH and HH, at least in some patients, and support the hypothesis that "push" factors may contribute to the etiology of HH.