[A case-control study on risk factors of hypospadias]

Hypospadias is one of the most commonly seen urogenital congenital malformations in males and to identify its etiological factors.

A hospital-based case-control study was conducted, with 107 hypospadias cases. Two matched controls per case were randomly selected. Both cases and controls were face to face interviewed with a uniformed questionnaire. Conditional logistic regression model was used for univariable and multivariate analysis on SAS 6.12 to estimate odds ratios (OR) and 95 per cent confidence internals (95% CI).

Data from multiple conditional logistic regression analysis showed that hypospadias was positively associated with maternal history of spontaneous abortion (OR = 3.87, 95% CI: 1.60 - 9.39), with threatened abortion in the first or second trimester (OR = 3.57, 95% CI: 1.31 - 9.64), with common cold accompanied fever in the first trimester (OR = 7.63, 95% CI: 2.50 - 23.24), with maternal drug (antibiotic, analgesiscs) exposure during the second trimester (OR = 16.46, 95% CI: 3.46 - 78.21), with paternal exposure to pesticides occupationally (OR = 3.70,95% CI: 1.49 - 9.16), with neonatal low birth weight (OR = 12.62, 95% CI: 2.97 - 53.67), but was negatively associated with maternal diet supplemented with protein in the first trimester (OR = 0.33, 95% CI: 0.15 - 0.74).

The risk factors of hypospadias seemed to include maternal history of spontaneous abortion, threatened abortion in the first or second trimester, maternal common cold accompanied fever in the first trimester, maternal drug exposure during the second trimester, paternal occupational exposure to pesticides, neonatal low birth weight. However, maternal diet supplemented with protein probably acted as the protective factor for neonatal hypospadias in the first trimester.