Unveiling Geographic Patterns in Critical Congenital Heart Defects: A Spatial Analysis of Selected air Pollutants

• Author / Creator

  Zargari, Ghazal

• Congenital heart defects (CHDs) are structural abnormalities of the heart present at birth, arising when the heart or nearby blood vessels don't develop properly during fetal growth. These conditions are a major public health concern, particularly for infants and young children, due to their complexity and the severity of their effects. Critical congenital heart defects (cCHDs) are a severe subset that require immediate medical intervention to prevent life-threatening complications. While genetic factors, such as chromosomal abnormalities, play a role in cCHDs, recent research has highlighted the potential impact of environmental factors, including air pollution, on their development. This has led to extensive studies investigating the relationship between air pollution and cCHDs.
  In this study, we use geographically weighted multinomial logistic regression (GWMLR) to explore the relationship between exposure to four key air pollutants—particulate matter with a diameter of 2.5 micrometers or less (PM2.5), ozone (O3), nitrogen dioxide (NO2), and air quality smoke (AQSMK)—and various subtypes of cCHDs. By analyzing data from 1,484 infants diagnosed with cCHDs, we examine how air pollutant exposure and cCHD incidence vary across different geographic regions.
  Our findings reveal significant patterns. PM2.5 exposure was associated with cCHDs in 0.32% of the locations studied, with these significant associations primarily clustered in Saskatchewan and Manitoba. When we compared the cCHD subtype distribution in these significant locations with the original dataset, we found notable discrepancies, highlighting the importance of accounting for spatial differences in air pollution exposure. These associations were found in small, localized areas, underscoring the need for targeted public health interventions.
  For ozone (O3) exposure, about 15% of locations showed significant impacts on cCHD subtypes, with most cases occurring in Alberta and a smaller number in Saskatchewan. While there were similarities in the distribution of cCHD subtypes across these regions, significant differences emerged when spatial adjustments were applied, further emphasizing the need to consider geographic variability in environmental health studies.
  Interestingly, no significant associations were found for NO2 and AQSMK exposure in any of the locations, suggesting that these pollutants may not have a direct impact on cCHD incidence in the studied population. However, when adjusting for these pollutants, we discovered significant associations between sex and cCHDs across all four pollutants, with AQSMK and NO2 showing a higher number of significant locations. Notably, the odds ratios in these cases were consistently below one, indicating a higher risk of cCHDs among male infants.
  The differences between the original dataset and the GWMLR results underscore the importance of using advanced modeling techniques to uncover complex patterns that may be missed by conventional methods. However, interpreting these findings can be challenging, especially given that most odds ratios were below one. This raises questions about the underlying mechanisms, which could include the choice of reference group, genetic predispositions, or undiagnosed chromosomal abnormalities within certain cCHD subtypes.
  Additionally, the influence of undiagnosed confounding factors and interactions between air pollutants and other environmental or genetic variables may complicate our understanding of the relationship between air pollution and cCHDs.
  This research provides valuable insights into the geographic variability of air pollution exposure and its impact on cCHD incidence. The findings can guide targeted public health interventions and inspire further research into the environmental factors contributing to cCHDs. By gaining a better understanding of how environmental factors influence CHD development, we can create more effective strategies to reduce the burden of cCHDs in affected communities.
  In conclusion, our study highlights the need for comprehensive strategies to address air pollution and its role in CHD incidence. Targeted interventions that consider geographic patterns, along with continued research into the mechanisms behind these associations, are crucial for improving health outcomes for individuals with cCHDs and reducing the global burden of congenital heart defects. Through collaborative and interdisciplinary research, we can advance our understanding of cCHD causes and develop effective prevention and management strategies to protect the health and well-being of vulnerable populations.

• Subjects / Keywords

  • Critical congenital heart defects
  • Prenatal exposure to air pollutants
  • Spatial analysis
  • Geographically weighted multinomial logistic regression

• Graduation date

  Fall 2024

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/r3-cr6p-7b61

• License

  This thesis is made available by the University of Alberta Library with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.