Onion and garlic intake and the odds of benign prostatic hyperplasia

To analyze the relationship between onion and garlic intake and benign prostatic hyperplasia (BPH), using data from a multicenter case-control study conducted in Italy.

A multicenter case-control study of 1369 patients with BPH and 1451 controls, admitted to the same hospitals for a wide spectrum of acute, non-neoplastic conditions, was conducted in Italy between 1991 and 2002. Information was collected by trained interviewers using a validated and reproducible food frequency questionnaire. Multivariate odds ratios (ORs) and 95% confidence intervals (CIs) were obtained after allowance for recognized confounding factors and energy intake.

Compared with nonusers, the multivariate ORs for the highest category of onion and garlic intake were 0.41 (95% CI 0.24 to 0.72) and 0.72 (95% CI 0.57 to 0.91), respectively. The combined OR for frequent users versus nonusers of both onion and garlic was 0.65 (95% CI 0.49 to 0.86). The inverse relationships were consistent across age strata.

This uniquely large data set from European populations showed an inverse association between allium vegetable consumption and BPH.