Elsevier

Journal of Pediatric Urology

Volume 10, Issue 6, December 2014, Pages 1076-1082
Journal of Pediatric Urology

Risk factors, prevalence trend, and clustering of hypospadias cases in Puerto Rico

https://doi.org/10.1016/j.jpurol.2014.03.014Get rights and content

Abstract

Objective

The aim was to determine the distribution pattern of hypospadias cases across a well-defined geographic space.

Materials and methods

The dataset for this study was produced by the Birth Defects Prevention and Surveillance System of the Department of Health of Puerto Rico (BDSS-PR), which linked the information of male newborns of the Puerto Rico Birth Cohort dataset (PRBC; n = 92,285) from 2007 to 2010. A population-based case–control study was conducted to determine prevalence trend and to estimate the potential effects of maternal age, paternal age, birth-related variables, and health insurance status on hypospadias. Two types of geographic information systems (GIS) methods (Anselin Local Moran's I and Getis-Ord G) were used to determine the spatial distribution of hypospadias prevalence.

Results

Birthweight (<2500 g), age of mother (40 + years), and private health insurance were associated with hypospadias as confirmed with univariate and multivariate analyses at 95% CI. A cluster of hypospadias cases was detected in the north-central region of Puerto Rico with both GIS methods (p ≤ 0.05).

Conclusions

The clustering of hypospadias prevalence provides an opportunity to assess the underlying causes of the condition and their relationships with geographical space.

Introduction

Hypospadias is traditionally defined by the anatomical position of the urethral meatus on the ventral surface of the penis other than close to the tip of the glans. This anatomical variation results from incomplete fusion of the urethral folds of the urethral spongiosum during intrauterine development and can range in position from the glans corona up to the perineum. Aside from variations in the localization of the urethral opening, hypospadias can also present with atypical shape of the urethral opening, of the glans, and of penile skin, various degrees of penile curvature, unilateral or bilateral cryptorchidism, among other variations in genital appearance. Severe hypospadias cases can also present with penile–scrotal transposition and/or enlarged prostatic utricle. In severe cases, clinical protocols for the management of intersexuality are commonly deployed. Given that hypospadias is not a monolithic clinical entity, we hypothesized that hypospadias prevalence is not uniformly distributed across space. The study of prevalence across space can provide valuable information about plausible gene/environment interactions that may underlie distinct distributions of cases. Moreover, the identification of hypospadias spatial clusters, if any, can be used to optimize the delivery of health services to manage the condition.

An impressive body of work on the etiology of hypospadias suggests that genetic and environmental factors are the main contributors to the high incidence of this male congenital condition. In fact, it has been suggested that, in the majority of cases, the etiology of this condition can be explained by a “two-hit hypothesis,” whereby genetic susceptibility plus environmental exposure increases the risk for having offspring with hypospadias [1], [2]. Early epidemiologic studies on incidence rates reported an increase of hypospadias in certain regions of the world including the United States [3], [4]. However, more recent studies do not support such a view; for a recent review see Fisch et al. [5]. One of these early studies showed a higher incidence of hypospadias cases in the eastern and central regions of the United States than the western region [4]. But this study, based on a nationwide surveillance program, the Birth Defects Monitoring Program, is limited by the fact that such a database was not built with a random sample of US births by representative geographic populations [5], [6].

We used the Puerto Rican archipelago as a case study to assess prevalence trend and to estimate the potential effects of maternal age, paternal age, birth-related variables, health insurance status, and the spatial distribution pattern of hypospadias prevalence. We found that birthweight (<2500 g), age of the mother (40 + years), and private health insurance were associated with hypospadias. In addition, clustering of confirmed hypospadias cases in the mainland of Puerto Rico was detected.

Section snippets

Materials and methods

The dataset for this analysis was produced by the Birth Defects Prevention and Surveillance System of the Department of Health of Puerto Rico (BDSS-PR), which linked the information of male newborns of the Puerto Rico Birth Cohort dataset (PRBC; n = 92,285) with a dataset of confirmed cases of hypospadias from 2007 to 2010. Initial diagnosis of hypospadias was made by a US board-certified physician in the birthing hospital and the birthing hospital reported each case to BDSS-PR routinely, as

Results

As in other countries, hypospadias is the most common urogenital tract condition in Puerto Rico. For the time period 2007–10, we found that hypospadias prevalence remained relatively constant with an average prevalence of 30.2/10,000 male live births (Fig. 1A). Analysis by comorbidity showed that 251 out of 279 hypospadias cases did not have another congenital condition, whereas 14 cases had one additional condition and 14 cases had two or more additional congenital conditions (Fig. 1B). Those

Discussion

The prevalence of hypospadias in Puerto Rico has remained relatively constant during the years 2007–10. The calculated prevalence was 30.2/10,000 male live births for this time period. This low prevalence allows us to interpret the odds ratio as a measure of risk. We found that 90% of these cases did not exhibit comorbid congenital conditions. Birthweight (<2500 g), age of the mother (40 + years), and private health insurance were found to be risk factors for having a newborn with hypospadias.

Conclusion

The clustering of hypospadias prevalence provides an opportunity to assess the underlying causes of the condition and their relationships with geographical space.

Conflict of interest

None.

Funding

None.

Ethical approval

This study was approved by the Institutional Review Board (IRB) Committee.

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