What is Congenital Heart Disease?

Congenital heart disease (CHD) represents the most prevalent form of congenital anomaly in the world, implicated in over 180,000 infant deaths annually, and stands as a significant contributor to lifelong disabilities. In Canada, the prevalence of CHD is 12.3 per 1,000 births, translating to approximately 4,400 newborns affected each year out of an annual birth tally of 358,000. The repercussions of CHD stretch far beyond the affected individuals, touching their families and exerting substantial pressure on the healthcare system.

Risk Factors

The etiology of CHD encompasses a broad spectrum of risk factors, many of which are not well understood. Research has identified a correlation between CHD risk and several factors, including genetic predispositions, maternal factors such as age and health conditions (e.g., pre-existing diabetes, gestational diabetes, rubella virus infection), environmental exposures, lifestyle behaviors (e.g., smoking, alcohol, and drug use during pregnancy), and assisted reproductive technology. However, it is important to acknowledge that many babies with CHD do not have any identifiable risk factors. Congenital anomalies can occur by chance, without a discernible underlying cause.

Bridging a Knowledge Gap

Research into the connections between congenital heart disease (CHD) development and socioeconomic status (SES) has been sparse, with inconsistent findings and a notable gap in understanding how maternal SES influences CHD risk. In 2019, in an effort to bridge this knowledge gap, researchers from BORN partnered with external experts on a project funded by the Canadian Institutes of Health Research (CIHR) to investigate the social determinants affecting maternal risk factors for CHD, utilizing data from the BORN registry.

Lower Socioeconomic Status Linked to Congenital Heart Disease in Newborns

This collaborative research effort has produced valuable insights, as documented in four published papers. The findings indicate an association between lower maternal SES—characterized by reduced household income, poverty, lower levels of education, and unemployment—and an increased risk of CHD in newborns. A striking disparity was observed in the distribution of CHD cases across different racial groups and residential locations. Notably, 38.4% of expectant mothers from the most economically disadvantaged neighborhoods were Black, compared to only 17.5% who were White. Black mothers faced a 40% higher chance of having a child with CHD compared to their White counterparts. Furthermore, the research identified a heightened risk of CHD among infants born to mothers living in rural areas as  opposed to urban settings.

Next Steps: Exploring Immigration and Neighborhood Socioeconomic Status

These findings highlight significant health equity challenges in the prevalence of CHD in Ontario, suggesting that socio-economic and racial disparities have a significant impact the disease development. To delve deeper into these health equity issues, BORN researchers are now collaborating with scientists at ICES Queen’s University. This new phase of research aims to explore the impact of maternal immigration status and neighborhood SES on the mortality rates among children with severe CHD, furthering our understanding of the complex socio-economic factors at play in CHD outcomes.

Rererences

1. Miao, Q., Dunn, S., Wen, S.W. et al. Association between maternal marginalization and infants born with congenital heart disease in Ontario Canada. BMC Public Health 23, 790 (2023). https://doi.org/10.1186/s12889-023-15660-5

2. Miao Q, Dunn S, Wen SW, Lougheed J, Sharif F, Walker M. Associations of congenital heart disease with deprivation index by rural-urban maternal residence: a population-based retrospective cohort study in Ontario, Canada. BMC pediatrics. 2022 Dec;22(1):1-1. doi: 10.1186/s12887-022-03498-6.

3. Miao Q, Dunn S, Wen SW, Lougheed J, Maxwell C, Reszel J, Hafizi K, Walker M. Association of maternal socioeconomic status and race with risk of congenital heart disease: a population-based retrospective cohort study in Ontario, Canada. BMJ Open 2022;12:e051020. doi: 10.1136/bmjopen-2021-051020.

4. Miao, Q., Dunn, S., Wen, S. W., Lougheed, J., Reszel, J., Lavin Venegas, C., & Walker, M. (2021). Neighbourhood maternal socioeconomic status indicators and risk of congenital heart disease. BMC Pregnancy and Childbirth, 21(1), 1-21. doi.org/10.1186/s12884-020-03512-8