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Prenatal Fine Particulate Matter (PM2.5) Exposure and the Riskof Pediatric Inguinal Hernia or Hydrocele: A
Eun Jung Kim1, Jin-Gon Bae2, Eun-Jung Koo3
1Department of Urban Planning, Keimyung University, Daegu 42601, Republic of Korea.
Insights
Maternal exposure to fine particulate matter (PM2.5) during pregnancy increases the risk of inguinal hernia or hydrocele in children. This prenatal air pollution may be a modifiable risk factor for these common pediatric surgical conditions.
Area of Science:
- Pediatric Surgery
- Environmental Health
- Reproductive Epidemiology
Background:
- Inguinal hernia and hydrocele are common pediatric surgical conditions linked to failed fetal development of the processus vaginalis.
- Prenatal fine particulate matter (PM2.5) exposure is associated with adverse perinatal outcomes, but its role in pediatric surgical anomalies is unclear.
Purpose of the Study:
- To investigate the association between maternal PM2.5 exposure during pregnancy and the risk of inguinal hernia or hydrocele in offspring.
Main Methods:
- Retrospective cohort study of 1093 mother-offspring pairs.
- Maternal residential PM2.5 levels estimated using kriging interpolation.
- Logistic regression analyzed trimester-specific PM2.5 exposure and risk of inguinal hernia/hydrocele.
Main Results:
- 53 offspring (4.85%) developed inguinal hernia or hydrocele.
- Second-trimester PM2.5 exposure was an independent risk factor (OR, 1.07 per µg/m³; p=0.028).
- A dose-response pattern observed; IQR increase associated with 64% higher risk (OR, 1.64).
Conclusions:
- Elevated maternal PM2.5 exposure during the second trimester is independently associated with increased risk of pediatric inguinal hernia or hydrocele.
- Prenatal air pollution may contribute to the persistence of the processus vaginalis.
- PM2.5 exposure represents a potentially modifiable environmental risk factor for these conditions.
Abstract:
Background/Objectives: Inguinal hernia and hydrocele are common pediatric surgical conditions resulting from failed obliteration of the processus vaginalis during fetal development. Although prenatal exposure to fine particulate matter (PM2.5) has been linked to adverse perinatal outcomes and congenital anomalies, its role in structurally defined pediatric surgical diseases remains unclear. We examined the association between maternal PM2.5 exposure during pregnancy and the risk of inguinal hernia or hydrocele in offspring. Methods: We performed a retrospective cohort study of 1093 mother-offspring pairs delivering at a tertiary referral center (July 2016-June 2019). Monthly residential PM2.5 levels were estimated at geocoded maternal addresses using kriging interpolation from fixed-site monitoring stations. Offspring diagnosed with inguinal hernia or hydrocele through March 2024 were identified using ICD-10 codes. Perinatal characteristics were compared using t-tests and chi-square tests, and multivariable logistic regression assessed trimester-specific PM2.5 exposure and risk. Results: During follow-up, 53 offspring (4.85%) developed inguinal hernia or hydrocele. Male sex (odds ratio [OR], 24.71; 95% CI, 5.95-102.54; p < 0.001) and second-trimester PM2.5 exposure (OR, 1.07 per µg/m3; 95% CI, 1.01-1.14; p = 0.028) were independent risk factors. A dose-response pattern was observed across quartiles of second-trimester exposure; an interquartile range increase was associated with a 64% higher risk (OR, 1.64). The model showed good discrimination (AUC, 0.804). Conclusions: Elevated maternal PM2.5 exposure during the second trimester was independently associated with increased risk of inguinal hernia or hydrocele in offspring. Prenatal air pollution may contribute to persistence of the processus vaginalis and represents a potentially modifiable environmental risk factor.
