Risk of congenital anomalies in children who have a sibling with cancer: A matched cohort study

PURPOSE

We assessed the risk of congenital anomalies in children who have a sibling with cancer.

METHODS

We performed a matched cohort study of children born between 2006 and 2022 in Quebec. The exposure was having a sibling with cancer. Exposed children were matched to unexposed children based on sex, number of siblings, birth order, and year. The outcome included heart defects, orofacial clefts, and other anomalies. Using conditional logistic regression, we estimated odds ratios (OR) and 95 % confidence intervals (CI) for the association between having a sibling with cancer and the likelihood of having a congenital anomaly.

RESULTS

A total of 2403 children who had a sibling with cancer were matched to 240,257 unexposed children. Congenital anomalies were more frequent in children who had a sibling with cancer compared with unexposed children (10.3 % vs 8.9 %). Overall, having a sibling with cancer was only weakly associated with congenital anomalies (OR 1.18, 95 % CI 1.04-1.35). Exposed children tended to have greater odds of polydactyly/syndactyly (OR 1.89, 95 % CI 1.11-3.21) and urinary defects (OR 1.50, 95 % CI 1.09-2.08) compared with unexposed children.

CONCLUSIONS

Children who have a sibling with cancer have an only weakly elevated risk of congenital anomalies.

Congenital anomalies during Covid-19: artifact of surveillance or a real TORCH?

Infections in the first trimester of pregnancy can be teratogenic, but the possibility that Covid-19 could lead to birth defects is unclear. We examined whether SARS-CoV-2 infection during pregnancy or exposure to pandemic conditions were associated with the risk of congenital anomalies. We carried out a retrospective study of 420,222 neonates born in Quebec, Canada in two time periods: prepandemic (January 1, 2017 to March 12, 2020) vs. pandemic (March 13, 2020 to March 31, 2022). We classified pandemic births as early (first trimester completed before the pandemic) or late (first trimester during the pandemic), and identified patients with SARS-CoV-2 infections during pregnancy. We applied (1) adjusted log-binomial regression models to assess the association between SARS-CoV-2 infection and congenital anomalies, and (2) autoregressive interrupted time series regression to analyze temporal trends in the monthly number of defects in all patients regardless of infection. In total, 29,263 newborns (7.0%) had a congenital anomaly. First trimester SARS-CoV-2 infections were not associated with a greater risk of birth defects compared with no infection (RR 1.07, 95% CI 0.59-1.95). However, births during the late pandemic period were more likely to be diagnosed with congenital microcephaly compared with prepandemic births (RR 1.44, 95% CI 1.21-1.71). Interrupted time series analysis confirmed that the frequency of microcephaly increased during the late pandemic period, whereas other anomalies did not. We conclude that Covid-19 is likely not teratogenic, but enhanced surveillance of anomalies among late pandemic births may have heightened the detection of infants with microcephaly.

Risk of birth defects in children of mothers with defects

BACKGROUND

There is evidence that women with congenital anomalies are at risk of having an infant with the same defect. However, the risk of having an infant with a different type of defect is less well described.

AIMS

We evaluated the extent to which offspring of women with congenital anomalies were at risk of having a birth defect, including defects that were similar to or different from their mother's.

METHODS

We analyzed a retrospective cohort of 1,311,532 infants born in Canada between 2006 and 2022. The exposure was a maternal congenital anomaly, and the outcome included birth defects in the newborn. We estimated risk ratios (RR) and confidence intervals (CI) for the association of specific maternal anomalies with the risk of having an infant with a similar or different defect using log-binomial regression models adjusted for patient characteristics.

RESULTS

While mothers with anomalies were at risk of having an infant with the same defect, associations with other types of defects were not as strong. For example, compared with no maternal anomaly, maternal urogenital defects were associated with up to 45 times the risk of having an infant with a similar urogenital defect (RR 45.33, 95 % CI 31.92-64.36), but <2 times the risk of having an infant with orofacial clefts (RR 1.89, 95 % CI 1.07-3.34) and clubfoot (RR 1.36, 95 % CI 1.02-1.81).

CONCLUSION

The findings suggest that maternal congenital anomalies are only weakly associated with occurrence of a different type of defect in offspring.

The Inclusion of Underrepresented Populations in Cardiovascular Genetics and Epidemiology

Novel genetic risk markers have helped us to advance the field of cardiovascular epidemiology and refine our current understanding and risk stratification paradigms. The discovery and analysis of variants can help us to tailor prognostication and management. However, populations underrepresented in cardiovascular epidemiology and cardiogenetics research may experience inequities in care if prediction tools are not applicable to them clinically. Therefore, the purpose of this article is to outline the barriers that underrepresented populations can face in participating in genetics research, to describe the current efforts to diversify cardiogenetics research, and to outline strategies that researchers in cardiovascular epidemiology can implement to include underrepresented populations. Mistrust, a lack of diverse research teams, the improper use of sensitive biodata, and the constraints of genetic analyses are all barriers for including diverse populations in genetics studies. The current work is beginning to address the paucity of ethnically diverse genetics research and has already begun to shed light on the potential benefits of including underrepresented and diverse populations. Reducing barriers for individuals, utilizing community-driven research processes, adopting novel recruitment strategies, and pushing for organizational support for diverse genetics research are key steps that clinicians and researchers can take to develop equitable risk stratification tools and improve patient care.

Association of maternal cancer with congenital anomalies in offspring

BACKGROUND

Congenital anomalies are common, but the possibility that maternal cancer increases the chance of having a child with a birth defect is not fully understood.

OBJECTIVES

To examine the association between maternal cancer before or during pregnancy and the risk of birth defects in offspring.

METHODS

We conducted a retrospective cohort study of live births in Quebec, Canada, between 1989 and 2022 using hospital data. The main exposure measure was maternal cancer before or during pregnancy. The outcome included birth defects detected in offspring during gestation or at birth. We estimated risk ratios (RR) and 95% confidence intervals (CI) for the association of maternal cancer with birth defects using log-binomial regression models adjusted for potential confounders.

RESULTS

In this study of 2,568,120 newborns, birth defects were present in 6.0% and 6.7% of infants whose mothers had cancer before or during pregnancy, respectively, compared with 5.7% of infants whose mothers never had cancer. Cancer during pregnancy was associated with heart (RR 1.58, 95% CI 1.03, 2.44), nervous system (RR 4.05, 95% CI 2.20, 7.46) and urinary defects (RR 1.72, 95% CI 1.01, 2.95). Among specific types of malignancies during pregnancy, breast cancer was the most prominent risk factor for birth defects (RR 1.55, 95% CI 1.02, 2.37). Cancer before pregnancy was not associated with any type of birth defect or with defects overall (RR 1.01, 95% CI 0.92, 1.11). Moreover, no specific type of cancer before pregnancy was associated with an increased risk of birth defects.

CONCLUSIONS

Maternal cancer during pregnancy is associated with the risk of congenital anomalies in offspring, however, cancer before pregnancy is not associated with this outcome.

The Impact of Chronic Disease on the Corrected QT (QTc) Value in Women in a British Columbia First Nations Population

BACKGROUND

Indigenous women have higher rates of chronic disease than Indigenous men and non-Indigenous women. Long QT syndrome (LQTS) can be inherited or acquired; the latter may occur with chronic disease. A prolonged corrected QT value (QTc) is an independent risk factor for ventricular arrhythmias and sudden death, but few studies have quantified the impact of chronic disease on the QTc. We assessed the association between chronic disease and QTc prolongation in a population of First Nations women previously ascertained to study a high rate of inherited LQTS due to a unique genetic (founder) variant in their community.

METHODS

This substudy focusing on women expands on the original research where patients with clinical features of LQTS and their relatives were assessed for genetic variants discovered to affect the QTc. Medical records were retrospectively reviewed and chronic diseases documented. Using multivariate linear regression, adjusting for the effect of genetic variants, age, and QTc-prolonging medications, we evaluated the association between chronic disease and the QTc.

RESULTS

In total, 275 women were included. After adjustments, a prolonged QTc was associated with coronary artery disease (26.5 ms, 95% confidence interval [CI] 9.0-44.1 ms; P = 0.003), conduction system disease (26.8 ms, 95% CI 2.2-51.4 ms; P = 0.033), rheumatoid arthritis (28.9 ms, 95% CI 12.7-45.1 ms; P = 0.001), and type 2 diabetes mellitus (17.9 ms, 95% CI 3.6-32.3 ms; P = 0.015).

CONCLUSIONS

This quantification of the association between chronic disease and QTc prolongation in an Indigenous cohort provides insight into the nongenetic determinants of QTc prolongation. Corroboration in other populations will provide evidence for generalisability of these results.

The Prevalence and Characteristics of Arrhythmic Mitral Valve Prolapse in Patients With Unexplained Cardiac Arrest

BACKGROUND

There is growing evidence that mitral valve prolapse (MVP) is associated with otherwise unexplained cardiac arrest (UCA). However, reports are hindered by the absence of a systematic ascertainment of alternative diagnoses.

OBJECTIVES

This study reports the prevalence and characteristics of MVP in a large cohort of patients with UCA.

METHODS

Patients were enrolled following an UCA, defined as cardiac arrest with no coronary artery disease, preserved left ventricular ejection fraction, and no apparent explanation on electrocardiogram. A comprehensive evaluation was performed, and patients were diagnosed with idiopathic ventricular fibrillation (IVF) if no cause was found. Echocardiography reports were reviewed for MVP. Patients with MVP were divided into 2 groups: those with IVF (AMVP) and those with an alternative diagnosis (nonarrhythmic MVP). Patient characteristics were then compared. The long-term outcomes of AMVP were reported.

RESULTS

Among 571 with an initially UCA, 34 patients had MVP (6%). The prevalence of definite MVP was significantly higher in patients with IVF than those with an alternative diagnosis (24 of 366 [6.6%] vs 5 of 205 [2.4%]; P = 0.03). Bileaflet prolapse was significantly associated with AMVP (18 of 23 [78%] vs 1 of 8 [12.5%]; P = 0.001; OR: 25.2). The proportion of patients with AMVP who received appropriate implantable cardioverter-defibrillator therapies over a median follow-up of 42 months was 21.1% (4 of 19).

CONCLUSIONS

MVP is associated with otherwise UCA (IVF), with a prevalence of 6.6%. Bileaflet prolapse appears to be a feature of AMVP, although future studies need to ascertain its independent association. A significant proportion of patients with AMVP received appropriate implantable cardioverter-defibrillator therapies during follow-up.

Validation of case definition algorithms for the ascertainment of congenital anomalies

BACKGROUND

Congenital anomalies (CA) are one of the leading causes of infant mortality and long-term disability. Many jurisdictions rely on health administrative data to monitor these conditions. Case definition algorithms can be used to monitor CA; however, validation of these algorithms is needed to understand the strengths and limitations of the data. This study aimed to validate case definition algorithms used in a CA surveillance system in British Columbia (BC), Canada.

METHODS

A cohort of births between March 2000 and April 2002 in BC was linked to the Health Status Registry (HSR) and the BC Congenital Anomalies Surveillance System (BCCASS) to identify cases and non-cases of specific anomalies within each surveillance system. Measures of algorithm performance were calculated for each CA using the HSR as the reference standard. Agreement between both databases was calculated using kappa coefficient. The modified Standards for Reporting Diagnostic Accuracy guidelines were used to enhance the quality of the study.

RESULTS

Measures of algorithm performance varied by condition. Positive predictive value (PPV) ranged between approximately 73%-100%. Sensitivity was lower than PPV for most conditions. Internal congenital anomalies or conditions not easily identifiable at birth had the lowest sensitivity. Specificity and negative predictive value exceeded 99% for all algorithms.

CONCLUSION

Case definition algorithms may be used to monitor CA at the population level. Accuracy of algorithms is higher for conditions that are easily identified at birth. Jurisdictions with similar administrative data may benefit from using validated case definitions for CA surveillance as this facilitates cross-jurisdictional comparison.

Management of Inherited Arrhythmia Syndromes: a HiRO Consensus Handbook on Process of Care

Inherited arrhythmia syndromes are rare genetic conditions that predispose seemingly healthy individuals to sudden cardiac arrest and death. The Hearts in Rhythm Organization is a multidisciplinary Canadian network of clinicians, researchers, patients, and families that aims to improve care for patients and families with inherited cardiac conditions, focused on those that confer predisposition to arrhythmia and sudden cardiac arrest and/or death. The field is rapidly evolving as research discoveries increase. A streamlined, practical guide for providers to diagnose and follow pediatric and adult patients with inherited cardiac conditions represents a useful tool to improve health system utilization, clinical management, and research related to these conditions. This review provides consensus care pathways for 7 conditions, including the 4 most common inherited cardiac conditions that confer predisposition to arrhythmia, with scenarios to guide investigation, diagnosis, risk stratification, and management. These conditions include Brugada syndrome, long QT syndrome, arrhythmogenic right ventricular cardiomyopathy and related arrhythmogenic cardiomyopathies, and catecholaminergic polymorphic ventricular tachycardia. In addition, an approach to investigating and managing sudden cardiac arrest, sudden unexpected death, and first-degree family members of affected individuals is provided. Referral to specialized cardiogenetic clinics should be considered in most cases. The intention of this review is to offer a framework for the process of care that is useful for both experts and nonexperts, and related allied disciplines such as hospital management, diagnostic services, coroners, and pathologists, in order to provide high-quality, multidisciplinary, standardized care.

Extended Risk of Mortality in Children with Inborn Errors of Metabolism: A Longitudinal Cohort Study

OBJECTIVES

To determine the long-term risk of mortality among children with inborn errors of metabolism.

STUDY DESIGN

We conducted a retrospective cohort study of 1750 children with inborn errors of metabolism (excluding mitochondrial disorders) and 1 036 668 children without errors of metabolism who were born in Quebec, Canada, between 2006 and 2019. Main outcome measures included all-cause and cause-specific mortality between birth and 14 years of age. We used adjusted survival regression models to estimate HRs and 95% CIs for the association between inborn errors of metabolism and mortality over time.

RESULTS

Mortality rates were greater for children with errors of metabolism than for unaffected children (69.1 vs 3.2 deaths per 10 000 person-years). During 7 702 179 person-years of follow-up, inborn errors of metabolism were associated with 21.2 times the risk of mortality compared with no error of metabolism (95% CI 17.23-26.11). Disorders of mineral metabolism were associated with greater mortality the first 28 days of life (HR 60.62, 95% CI 10.04-365.98), and disorders of sphingolipid metabolism were associated with greater mortality by 1 year (HR 284.73, 95% CI 139.20-582.44) and 14 years (HR 1066.00, 95% CI 298.91-3801.63). Errors of metabolism were disproportionately associated with death from hepatic/digestive (HR 208.21, 95% CI 90.28-480.22), respiratory (HR 116.57, 95% CI 71.06-191.23), and infectious causes (HR 119.83, 95% CI 40.56-354.04).

CONCLUSIONS

Children with errors of metabolism have a considerably elevated risk of mortality before 14 years, including death from hepatic/digestive, respiratory, and infectious causes. Targeting these causes of death may help improve long-term survival.

Sex Differences and Utility of Treadmill Testing in Long‐QT Syndrome

Background

Diagnosis of congenital long‐QT syndrome (LQTS) is complicated by phenotypic ambiguity, with a frequent normal‐to‐borderline resting QT interval. A 3‐step algorithm based on exercise response of the corrected QT interval (QTc) was previously developed to diagnose patients with LQTS and predict subtype. This study evaluated the 3‐step algorithm in a population that is more representative of the general population with LQTS with milder phenotypes and establishes sex‐specific cutoffs beyond the resting QTc.

Methods and Results

We identified 208 LQTS likely pathogenic or pathogenic KCNQ1 or KCNH2 variant carriers in the Canadian NLQTS (National Long‐QT Syndrome) Registry and 215 unaffected controls from the HiRO (Hearts in Rhythm Organization) Registry. Exercise treadmill tests were analyzed across the 5 stages of the Bruce protocol. The predictive value of exercise ECG characteristics was analyzed using receiver operating characteristic curve analysis to identify optimal cutoff values. A total of 78% of male carriers and 74% of female carriers had a resting QTc value in the normal‐to‐borderline range. The 4‐minute recovery QTc demonstrated the best predictive value for carrier status in both sexes, with better LQTS ascertainment in female patients (area under the curve, 0.90 versus 0.82), with greater sensitivity and specificity. The optimal cutoff value for the 4‐minute recovery period was 440 milliseconds for male patients and 450 milliseconds for female patients. The 1‐minute recovery QTc had the best predictive value in female patients for differentiating LQTS1 versus LQTS2 (area under the curve, 0.82), and the peak exercise QTc had a marginally better predictive value in male patients for subtype with (area under the curve, 0.71). The optimal cutoff value for the 1‐minute recovery period was 435 milliseconds for male patients and 455 milliseconds for femal patients.

Conclusions

The 3‐step QT exercise algorithm is a valid tool for the diagnosis of LQTS in a general population with more frequent ambiguity in phenotype. The algorithm is a simple and reliable method for the identification and prediction of the 2 major genotypes of LQTS.

A Call to Action: Optimizing Indigenous Cardiovascular Health in Canada

Indigenous peoples in Canada continue to experience substantially higher rates of cardiovascular disease compared to non-Indigenous Canadians. Herein, we 1) identify upstream factors contributing to the current state of Indigenous cardiovascular health, 2) suggest culturally responsive approaches to engage Indigenous patients and communities, and 3) propose strategies to enhance collaborative, culturally safe research and healthcare access in Indigenous communities in Canada.

Association of first trimester anaesthesia with risk of congenital heart defects in offspring

BACKGROUND

A substantial number of pregnant women require anaesthesia for non-obstetric surgery, but the risk to fetal heart development is unknown. We assessed the relationship between first trimester anaesthesia and risk of congenital heart defects in offspring.

METHODS

We conducted a longitudinal cohort study of 2 095 300 pregnancies resulting in live births in hospitals of Quebec, Canada, between 1990 and 2016. We identified women who received general or local/regional anaesthesia in the first trimester, including anaesthesia between 3 and 8 weeks post-conception, the critical weeks of fetal cardiogenesis. The main outcome measures were critical and non-critical heart defects in offspring. We estimated risk ratios (RR) and 95% confidence intervals (CI) for the association of first trimester anaesthesia with congenital heart defects, using log-binomial regression models adjusted for maternal characteristics.

RESULTS

There were 107.3 congenital heart defects per 10 000 infants exposed to anaesthesia, compared with 87.2 per 10 000 unexposed infants. Anaesthesia between 3 and 8 weeks post-conception was associated with 1.50 times the risk of congenital heart defects (95% CI 1.11-2.03), compared with no anaesthesia. Anaesthesia between 5 and 6 weeks post-conception was associated with 1.84 times the risk (95% CI 1.10-3.08). Associations were driven mostly by general anaesthesia, which was associated with 2.49 times the risk between weeks 5 and 6 post-conception (95% CI 1.40-4.44).

CONCLUSIONS

General anaesthesia during critical periods of fetal heart development may increase the risk of congenital heart defects. Further research is needed to confirm that anaesthetic agents are cardiac teratogens.

Is there a way to reduce the inequity in variant interpretation on the basis of ancestry?

The underrepresentation of non-European ancestry groups in current genomic databases complicates interpretation of their genetic test results, yielding a much higher prevalence of variants of uncertain significance (VUSs). Such VUS findings can frustrate the goals of genetic testing, create anxiety in patients, and lead to unnecessary medical interventions. Approaches to addressing underrepresentation of people with genetic ancestries other than European are being undertaken by broad-based recruitment efforts. However, some underrepresented groups have concerns that might preclude participation in such efforts. We describe here two initiatives aimed at meeting the needs of underrepresented ancestry groups in genomic datasets. The two communities, the Sephardi Jewish community in New York and First Peoples of Canada, have very different concerns about contributing to genomic research and datasets. Sephardi concerns focus on the possible negative effects of genetic findings on the marriage prospects of family members. Canadian Indigenous populations seek control over the research uses to which their genetic data would be put. Both cases involve targeted efforts to respond to the groups' concerns; these efforts include governance models aimed at ensuring that the data are used primarily to inform clinical test analyses and at achieving successful engagement and participation of community members. We suggest that these initiatives could provide models for other ancestral groups seeking to improve the accuracy and utility of clinical genetic testing while respecting the underlying preferences and values of community members with regard to the use of their genetic data.

Association of Birth Defects With Child Mortality Before Age 14 Years

IMPORTANCE

Causes of death in children with birth defects are poorly understood.

OBJECTIVE

To determine mortality rates by cause of death in children with and without birth defects.

DESIGN, SETTING, AND PARTICIPANTS

This longitudinal cohort study included a population-based sample of 1 037 688 children and was conducted in all hospitals in Quebec, Canada, with 7 700 596 person-years of follow-up between birth and age 14 years (April 1, 2006, to March 31, 2020).

EXPOSURES

Presence or absence of a birth defect.

MAIN OUTCOMES AND MEASURES

Outcomes were all-cause and cause-specific mortality. Hazard ratios (HRs) and 95% CIs were computed for the association between birth defects and mortality with Cox proportional hazards models adjusted for patient characteristics.

RESULTS

Among the 1 037 688 children in the cohort, 95 566 had birth defects (56.5% boys). There were 532 542 boys in the cohort (51.3%), and mean (SD) age at the end of follow-up was 7.42 (3.72) years. There were 918 deaths among children with defects, and the mean (SD) age was 0.93 (2.07) years at death; there were 1082 deaths among the 942 122 children without defects, and the mean (SD) age at death was 0.50 (1.51) years. Mortality rates were higher for children with birth defects compared with no defect (1.3 vs 0.2 deaths per 1000 person-years, respectively). Girls (HR, 5.66; 95% CI, 4.96-6.47) and boys (HR, 4.69; 95% CI, 4.15-5.29) with birth defects had an elevated risk of death before 14 years compared with unaffected children. Birth defects were associated with mortality from circulatory (HR, 26.59; 95% CI, 17.73-39.87), respiratory (HR, 23.03; 95% CI, 15.09-35.14), and digestive causes (HR, 31.77; 95% CI, 11.87-85.04), but anomalies were rarely listed as the cause of death. Compared with children with no defect, those with birth defects were at greatest risk of death between 28 and 364 days of life.

CONCLUSIONS AND RELEVANCE

This cohort study of 1 037 688 children suggests that birth defects were strongly associated with mortality owing to circulatory, respiratory, and digestive causes. This finding suggests that the contribution of birth defects may be underestimated in mortality statistics.

Rare disorders have many faces: in silico characterization of rare disorder spectrum

Background

The diagnostic journey for many rare disease patients remains challenging despite use of latest genetic technological advancements. We hypothesize that some patients remain undiagnosed due to more complex diagnostic scenarios that are currently not considered in genome analysis pipelines. To better understand this, we characterized the rare disorder (RD) spectrum using various bioinformatics resources (e.g., Orphanet/Orphadata, Human Phenotype Ontology, Reactome pathways) combined with custom-made R scripts.

Results

Our in silico characterization led to identification of 145 borderline-common, 412 rare and 2967 ultra-rare disorders. Based on these findings and point prevalence, we would expect that approximately 6.53%, 0.34%, and 0.30% of individuals in a randomly selected population have a borderline-common, rare, and ultra-rare disorder, respectively (equaling to 1 RD patient in 14 people). Importantly, our analyses revealed that (1) a higher proportion of borderline-common disorders were caused by multiple gene defects and/or other factors compared with the rare and ultra-rare disorders, (2) the phenotypic expressivity was more variable for the borderline-common disorders than for the rarer disorders, and (3) unique clinical characteristics were observed across the disorder categories forming the spectrum.

Conclusions

Recognizing that RD patients who remain unsolved even after genome sequencing might belong to the more common end of the RD spectrum support the usage of computational pipelines that account for more complex genetic and phenotypic scenarios.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13023-022-02217-9.

Implementation of the BC Congenital Anomalies Surveillance System (BCCASS)

SETTING

Congenital anomalies (CAs) can cause lifelong morbidity and accounted for 23.2% of infant deaths from 2003 to 2007. In British Columbia (BC), surveillance of CAs has been irregular since the early 2000s. To enhance CAs surveillance in BC, the Public Health Agency of Canada has provided funding for the implementation of the BC Congenital Anomalies Surveillance System (BCCASS).

INTERVENTION

BCCASS is a population-based surveillance system. The system leverages existing administrative data sources that capture information regarding vital events, disease status, drug prescription, and healthcare utilization. The system uses a series of algorithms to capture specific CAs diagnoses, some of which are further validated with the support of the Provincial Advisory Committee. This Advisory Committee is a multi-stakeholder coalition that includes the BC Office of the Provincial Health Officer, subject matter experts, data partners, users, and academia, and acts to provide support, expertise, and strategic guidance to BCCASS.

OUTCOMES

Through BCCASS, prevalence and historical trends for 35 CAs in BC are available. Information pertaining to maternal place of residence, risk, and protective factors can be used for association studies such as links to environmental hazards and cluster analysis.

IMPLICATIONS

BCCASS is a cost-effective and sustainable system that leverages existing data sources necessary to understand the overall burden of CAs across the BC population. This is fundamental to support data-driven decisions around policy development, program planning, and evaluation of preventive measures. Strong coalitions with stakeholders are instrumental to ensure successful implementation and expansion in the future.

Cascade testing for inherited arrhythmia conditions: Experiences and attitudes of family communication approaches for a Canadian cohort

Inherited arrhythmia conditions (IAC) can lead to sudden cardiac death at any age, and relatives of an affected person have up to a 50% chance of inheriting the condition and are at risk for developing features. Cascade testing is a stepwise approach for identifying relatives at risk for IACs through clinical screening and genetic testing. Early detection can reduce morbidity and mortality for affected individuals and determine potential risk mitigation strategies for relatives. However, cardiovascular genetic studies have reported an incomplete uptake of cascade testing in at-risk relatives. We explored patient perspectives on cascade testing for IACs and alternative approaches to family communication. Twelve semi-structured phone interviews were conducted with probands of the British Columbia Inherited Arrhythmia Program confirmed to carry a pathogenic or likely pathogenic variant in a gene associated with an IAC. Thematic analysis of transcripts through an iterative coding process revealed five main themes: (a) a stepwise approach is followed in disclosing risk to relatives, (b) relatives' autonomy in cascade testing is supported, (c) lived experience with the condition influences disclosure and uptake of cascade testing, (d) collaborative approach to informing relatives reduces negative impact of disclosure, and (e) direct contact from a healthcare provider is viewed as acceptable. The findings highlight this patient cohort's experiences and opinions with approaches to disclosure and demonstrate their understanding and acceptance of their relatives' approaches to cascade testing. In addition, while the notion of direct contact was generally accepted, a collaborative approach to contacting relatives between the proband and provider may be most effective.

OUP accepted manuscript

Aims

Genetic testing is recommended in specific inherited heart diseases but its role remains unclear and it is not currently recommended in unexplained cardiac arrest (UCA). We sought to assess the yield and clinical utility of genetic testing in UCA using whole-exome sequencing (WES).

Methods and results

Survivors of UCA requiring external defibrillation were included from the Cardiac Arrest Survivor with Preserved Ejection fraction Registry. Whole-exome sequencing was performed, followed by assessment of rare variants in previously reported cardiovascular disease genes. A total of 228 UCA survivors (mean age at arrest 39 ± 13 years) were included. The majority were males (66%) and of European ancestry (81%). Following advanced clinical testing at baseline, the likely aetiology of cardiac arrest was determined in 21/228 (9%) cases. Whole-exome sequencing identified a pathogenic or likely pathogenic (P/LP) variant in 23/228 (10%) of UCA survivors overall, increasing the proportion of ‘explained’ cases from 9% only following phenotyping to 18% when combining phenotyping with WES. Notably, 13 (57%) of the 23 P/LP variants identified were located in genes associated with cardiomyopathy, in the absence of a diagnosis of cardiomyopathy at the time of arrest.

Conclusions

Genetic testing identifies a disease-causing variant in 10% of apparent UCA survivors. The majority of disease-causing variants was located in cardiomyopathy-associated genes, highlighting the arrhythmogenic potential of such variants in the absence of an overt cardiomyopathy diagnosis. The present study supports the use of genetic testing including assessment of arrhythmia and cardiomyopathy genes in survivors of UCA.

Time trends, geographic variation and risk factors for gastroschisis in Canada: A population-based cohort study 2006-2017

BACKGROUND

Previous studies showed increases in rates of gastroschisis in Canada in the first decade of the 21st century.

OBJECTIVE

We sought to examine the epidemiologic characteristics of gastroschisis in Canada in recent years.

METHODS

We conducted a retrospective population-based cohort study of all livebirths and stillbirths delivered in Canada (excluding Quebec) from 2006 to 2017, with information obtained from the Canadian Institute for Health Information. Gastroschisis rates by maternal age, region of residence, and maternal and infant characteristics were quantified using prevalence rate ratios (RR) and 95% confidence intervals (CI). Log-binomial regression was used to quantify the associations between risk factors and gastroschisis.

RESULTS

There were 1314 gastroschisis cases among 3 364 116 births. The prevalence rate was 3.7 per 10 000 total births in 2006 and 3.4 per 10 000 total births in 2017, with substantial annual variation in rates. The proportion of mothers aged 20-24 years decreased from 16.5% in 2006 to 11.3% in 2017, while the proportion of mothers aged <20 years halved from 4.8% to 2.3%. The prevalence of gastroschisis at birth remained unchanged among mothers aged <20, 20-24 and 30-49 years but increased among mothers aged 25-29 years. The age-adjusted prevalence rate of gastroschisis increased across the period (for 2016-2017 versus 2006-2007 rate ratio [RR] 1.28, 95% CI 1.05, 1.56), and there was substantial regional variation. Risk factors included problematic use of substances (RR 2.61, 95% CI 2.01, 3.39) and hypothyroidism (RR 2.76, 95% CI 1.56, 4.88). There was a North-to-South difference in gastroschisis prevalence (adjusted RR Far North compared with South 1.54, 95% CI 1.11, 2.15).

CONCLUSION

Gastroschisis birth prevalence rates in Canada have stabilised in recent years compared with the increase documented previously. The substantial geographic variation and North-to-South difference in gastroschisis prevalence may indicate variation in socio-economic status, lifestyle and nutritional patterns.

Return of Results Policies for Genomic Research: Current Practices & The Hearts in Rhythm Organization Approach

Research teams developing biobanks and/or genomic databases must develop policies for the disclosure and reporting of potentially actionable genomic results to research participants. Currently, a broad range of approaches to the return of results exist, with some studies opting for non-disclosure of research results while others follow clinical guidelines for the return of potentially actionable findings from sequencing. In this review, we describe current practices and highlight decisions a research team must make when designing a return of results policy, from informed consent to disclosure practices and clinical validation options. The unique challenges of returning incidental findings in cardiac genes, including reduced penetrance and the lack of clinical screening standards for phenotype-negative individuals are discussed. Lastly, the National Hearts in Rhythm Organization (HiRO) Registry approach is described to provide a rationale for the selective return of field-specific variants to those participating in disease-specific research. Our goal is to provide researchers with a resource when developing a return of results policy tailored for their research program, based on unique factors related to study design, research team composition and availability of clinical resources.

Variant Reinterpretation in Survivors of Cardiac Arrest With Preserved Ejection Fraction (the Cardiac Arrest Survivors With Preserved Ejection Fraction Registry) by Clinicians and Clinical Commercial Laboratories

BACKGROUND

Following an unexplained cardiac arrest, clinical genetic testing is increasingly becoming standard of care. Periodic review of variant classification is required, as reinterpretation can change the diagnosis, prognosis, and management of patients and their relatives.

METHODS

This study aimed to develop and validate a standardized algorithm to facilitate clinical application of the 2015 American College of Medical Genetics and Association for Molecular Pathology guidelines for the interpretation of genetic variants. The algorithm was applied to genetic results in the Cardiac Arrest Survivors With Preserved Ejection Fraction Registry, to assess the rate of variant reclassification over time. Variant classifications were then compared with the classifications of 2 commercial laboratories to determine the rate and identify sources of variant interpretation discordance.

RESULTS

Thirty-one percent of participants (40 of 131) had at least 1 genetic variant with a clinically significant reclassification over time. Variants of uncertain significance were more likely to be downgraded (73%) to benign than upgraded to pathogenic (27%; P=0.03). For the second part of the study, 50% (70 of 139) of variants had discrepant interpretations (excluding benign variants), provided by at least 1 team.

CONCLUSIONS

Periodic review of genetic variant classification is a key component of follow-up care given rapidly changing information in the field. There is potential for clinical care gaps with discrepant variant interpretations, based on the interpretation and application of current guidelines. The development of gene- and disease-specific guidelines and algorithms may provide an opportunity to further standardize variant interpretation reporting in the future. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT00292032.

Stillbirth in Canada: anachronistic definition and registration processes impede public health surveillance and clinical care

The archaic definition and registration processes for stillbirth currently prevalent in Canada impede both clinical care and public health. The situation is fraught because of definitional problems related to the inclusion of induced abortions at ≥20 weeks’ gestation as stillbirths: widespread uptake of prenatal diagnosis and induced abortion for serious congenital anomalies has resulted in an artefactual temporal increase in stillbirth rates in Canada and placed the country in an unfavourable position in international (stillbirth) rankings. Other problems with the Canadian stillbirth definition and registration processes extend to the inclusion of fetal reductions (for multi-fetal pregnancy) as stillbirths, and the use of inconsistent viability criteria for reporting stillbirth. This paper reviews the history of stillbirth registration in Canada, provides a rationale for updating the definition of fetal death and recommends a new definition and improved processes for fetal death registration. The recommendations proposed are intended to serve as a starting point for reformulating issues related to stillbirth, with the hope that building a consensus regarding a definition and registration procedures will facilitate clinical care and public health.

Association of the CPT1A p.P479L Metabolic Gene Variant With Childhood Respiratory and Other Infectious Illness in Nunavut

Objective: Infectious illness, including lower respiratory tract infection (LRTI), is a leading cause of childhood morbidity and infant mortality in Inuit children in Nunavut Canada. The carnitine palmitoyltransferase 1A (CPT1A) p.P479L variant is common in arctic Indigenous populations of Alaska, Canada, and Greenland. CPT1A is a fatty acid oxidation enzyme expressed in the liver, immunocytes and other tissues, and is needed to use fats for energy during fasting. Previous association of the variant with early childhood infectious illness and infant death has been challenged because of sample size and limited adjustment for confounders. We evaluated whether the p.P479L variant is associated with infectious illness in Inuit children of Nunavut, Canada. Methods: We conducted a retrospective clinical chart review of 2,225 Inuit children (0-5 years) for infectious illness (including otitis media, gastroenteritis, and hospital admission for LRTI), prenatal, perinatal, and socioeconomic indicators, subsequently linking to CPT1A genotype. Multivariable logistic regression adjusted for birth characteristics, breastfeeding, maternal smoking, food insecurity, and socioeconomic indicators. Results: Overall, 27% of children were hospitalized for LRTI, 86% had otitis media and 50% had gastroenteritis. The p.P479L allele frequency was 0.82. In multivariable analysis, p.P479L homozygosity was associated with LRTI admission (aOR:2.88 95%CI:1.46-5.64), otitis media (aOR:1.83, 95%CI:1.05-3.21), and gastroenteritis (aOR:1.74, 95%CI:1.09-2.77), compared to non-carriers. Conclusion: Children homozygous for the p.P479L variant were more likely to experience infectious illness than non-carriers, including hospitalization for respiratory tract infections. Given the role of CPT1A in immunocytes, our findings indicate that more study is needed to determine if there is a role of the variant in immune response. Continued Inuit involvement is essential when considering next steps.

Barriers and Considerations for Diagnosing Rare Diseases in Indigenous Populations

Advances in omics and specifically genomic technologies are increasingly transforming rare disease diagnosis. However, the benefits of these advances are disproportionately experienced within and between populations, with Indigenous populations frequently experiencing diagnostic and therapeutic inequities. The International Rare Disease Research Consortium (IRDiRC) multi-stakeholder partnership has been advancing toward the vision of all people living with a rare disease receiving an accurate diagnosis, care, and available therapy within 1 year of coming to medical attention. In order to further progress toward this vision, IRDiRC has created a taskforce to explore the access barriers to diagnosis of rare genetic diseases faced by Indigenous peoples, with a view of developing recommendations to overcome them. Herein, we provide an overview of the state of play of current barriers and considerations identified by the taskforce, to further stimulate awareness of these issues and the passage toward solutions. We focus on analyzing barriers to accessing genetic services, participating in genomic research, and other aspects such as concerns about data sharing, the handling of biospecimens, and the importance of capacity building.

Severe maternal morbidity surveillance: Monitoring pregnant women at high risk for prolonged hospitalisation and death

BACKGROUND

There is no international consensus on the definition and components of severe maternal morbidity (SMM).

OBJECTIVES

To propose a comprehensive definition of SMM, to create an empirically justified list of SMM types and subtypes, and to use this to examine SMM in Canada.

METHODS

Severe maternal morbidity was defined as a set of heterogeneous maternal conditions known to be associated with severe illness and with prolonged hospitalisation or high case fatality. Candidate SMM types/subtypes were evaluated using information on all hospital deliveries in Canada (excluding Quebec), 2006-2015. SMM rates for 2012-2016 were quantified as a composite and as SMM types/subtypes. Rate ratios and population attributable fractions (PAF) associated with overall and specific SMM types/subtypes were estimated in relation to length of hospital stay (LOS > 7 days) and case fatality.

RESULTS

There were 22 799 cases of SMM subtypes (among 1 418 545 deliveries) that were associated with a prolonged LOS or high case fatality. Between 2012 and 2016, the composite SMM rate was 16.1 (95% confidence interval [CI] 15.9, 16.3) per 1000 deliveries. Severe pre-eclampsia and HELLP syndrome (514.6 per 100 000 deliveries), and severe postpartum haemorrhage (433.2 per 100 000 deliveries) were the most common SMM types, while case fatality rates among SMM subtypes were highest among women who had cardiac arrest and resuscitation (241.1 per 1000), hepatic failure (147.1 per 1000), dialysis (67.6 per 1000), and cerebrovascular accident/stroke (51.0 per 1000). The PAF for prolonged hospital stay related to SMM was 17.8% (95% CI 17.3, 18.3), while the PAF for maternal death associated with SMM was 88.0% (95% CI 74.6, 94.4).

CONCLUSIONS

The proposed definition of SMM and associated list of SMM subtypes could be used for standardised SMM surveillance, with rate ratios and PAFs associated with specific SMM types/subtypes serving to inform clinical practice and public health policy.

Inflammatory Bowel Disease and Risk of Birth Defects in Offspring

BACKGROUND AND AIMS

The relationship between inflammatory bowel disease in pregnancy and birth defects is not understood. We evaluated whether Crohn's disease and ulcerative colitis in pregnant women were associated with the risk of birth defects in the offspring.

METHODS

We undertook a retrospective cohort study of 2 184 888 pregnancies in Quebec, Canada, between 1989 and 2016. We calculated risk ratios [RR] and 95% confidence intervals [CI] for the association between inflammatory bowel disease and the risk of birth defects, using generalised estimating equations adjusted for maternal characteristics. We assessed associations in the period before 2000, when immunosuppressive biologic therapy and folic acid food fortification were not yet available, compared with the period after 2000 when these interventions were more widespread.

RESULTS

This study included 13 099 women with Crohn's disease and 7798 with ulcerative colitis. Crohn's disease was associated with 1.90 times [95% CI 1.10-3.28] the risk of abdominal wall defects [gastroschisis, omphalocoele, and diaphragmatic hernia] and ulcerative colitis was associated with 1.53 times [95% CI 1.02-2.30] the risk of central nervous system defects. The association of Crohn's disease with abdominal wall defects was stronger before 2000 [RR 3.62, 95% CI 1.71-7.67] than after 2000 [RR 1.23, 95% CI 0.55-2.75]. Ulcerative colitis was associated with central nervous system defects regardless of time period.

CONCLUSIONS

These findings suggest that inflammatory bowel disease is associated with the risk of abdominal wall and central nervous system defects, and that introduction of immunobiologic medications is unlikely to be associated with added risk.

PODCAST

This article has an associated podcast which can be accessed at https://academic.oup.com/ecco-jcc/pages/podcast.

Understanding the personal and community impact of long QT syndrome: A perspective from Gitxsan women

There is a disproportionately high rate of hereditary long QT syndrome (LQTS) in Northern British Columbia First Nations people, largely due to a novel missense variant in KCNQ1 (p.V205M). The variant has been previously described predisposing those affected to syncope, arrhythmia, and sudden death. Although the biological aspects of LQTS have been explored extensively, less research has been done into the impact of living with a genetic variant that predisposes one to sudden death, and no previous studies have provided cultural insights from a First Nations community. The goal of this study was to explore what facilitates and hinders resiliency and coping for those living with LQTS. Participants were invited to partake in their choice of one-to-one interviews, Photovoice, and Talking Circles. This paper presents the findings from the interview portion of the study. Interviews were recorded, transcribed, and analyzed qualitatively using the systematic text condensation method. Ten women shared their personal experiences of living with LQTS through individual interviews. Half of the women had tested positive for the p.V205M variant, and the other half were awaiting results. In general, learning about a LQTS diagnosis was perceived as traumatic, with gradual acceptance that led to coping. The main factors found to facilitate resiliency and coping were positive family relationships, spirituality, and knowledge about LQTS. The main factors found to hinder resiliency and coping were a poor understanding of the biological or clinical aspects of LQTS, conflicting medical advice (especially regarding physical activity) and LQTS not being taken seriously by social contacts and healthcare providers. It appears that learning to live with LQTS is an ongoing process, requiring balance and interconnectedness between all aspects of well-being.

Indigenous Genomic Databases: Pragmatic Considerations and Cultural Contexts

The potential to grow genomic knowledge and harness the subsequent clinical benefits has escalated the building of background variant databases (BVDs) for genetic diagnosis across the globe. Alongside the upsurge of this precision medicine, potential benefits have been highlighted for both rare genetic conditions and other diagnoses. However, with the ever-present “genomic divide,” Indigenous peoples globally have valid concerns as they endure comparatively greater health disparities but stand to benefit the least from these novel scientific discoveries and progress in healthcare. The paucity of Indigenous healthcare providers and researchers in these fields contributes to this genomic divide both in access to, and availability of culturally safe, relevant and respectful healthcare using this genetic knowledge. The vital quest to provide equitable clinical research, and provision and use of genomic services and technologies provides a strong rationale for building BVDs for Indigenous peoples. Such tools would ground their representation and participation in accompanying genomic health research and benefit acquisition. We describe two, independent but highly similar initiatives–the “Silent Genomes” in Canada and the “Aotearoa Variome” in New Zealand–as exemplars that have had to address the aforementioned issues and work to create Indigenous BVDs with these populations. Taking into account the baseline inequities in genomic medicine for Indigenous populations and the ongoing challenges of implementing genomic research with Indigenous communities, we provide a rationale for multiple changes required that will assure communities represented in BVDs, as well as Indigenous researchers, that their participation will maximize benefits and minimize risk.

Neonatal hypoglycemia and the CPT1A P479L variant in term newborns: A retrospective cohort study of Inuit newborns from Kivalliq Nunavut

Introduction

Neonatal hypoglycemia (NH) in the first days of life can largely be prevented by recognizing those at risk and managing accordingly. The CPT1A P479L variant is prevalent in northern Indigenous populations and is a possible risk factor for hypoglycemia. We report on NH incidence in the Kivalliq region of Nunavut, where all Inuit newborns are screened for NH.

Methods

We reviewed clinical charts of 728 Inuit newborns from Kivalliq (January 1, 2010 to December 31, 2013) for blood glucose (BG) levels and infant/maternal characteristics, linking to CPT1A genotype; 616 newborns had BG data from 2 to 48 hours of life. NH was defined using Canadian Paediatric Society guidelines (≤2.0 mmol/L at 2 hours, <2.6 mmol/L at 2 to 48 hours).

Results

NH was documented in 21.4% overall, 24.4% of at-risk newborns and 19.5% of term newborns with no risk factors (≥37 weeks gestation, term-NRF). NH was documented in 22.0% of CPT1A P479L homozygous, 19.8% of P479L heterozygous and 4.8% of noncarrier term-NRF newborns. With multivariable logistic regression, the adjusted ORs for developing NH in term-NRF newborns was 4.97 for CPT1A P479L homozygotes (95% confidence interval [CI]:0.65-38.35, P=0.19) and 4.71 for P479L heterozygotes (95% CI:0.57-37.89, P=0.15).

Conclusion

Term-NRF newborns had a higher NH incidence than previously reported, similar to that for at-risk newborns, possibly due to the CPT1A P479L variant. Since only Inuit newborns from Kivalliq are screened for NH, further study of long-term outcomes of NH in this population and the role of the P479L variant are warranted to determine if neonatal BG screening is indicated in all Inuit newborns.

Cardiac arrest in a mother and daughter and the identification of a novel RYR2 variant, predisposing to low penetrant catecholaminergic polymorphic ventricular tachycardia in a four‐generation Canadian family

Background

Catecholaminergic polymorphic ventricular tachycardia (CPVT) is a rare inherited arrhythmia syndrome characterized by adrenergically driven ventricular arrhythmia predominantly caused by pathogenic variants in the cardiac ryanodine receptor (RyR2). We describe a novel variant associated with cardiac arrest in a mother and daughter.

Methods

Initial sequencing of the RYR2 gene identified a novel variant (c.527G > T, p.R176L) in the index case (the mother), and her daughter. Structural analysis demonstrated the variant was located within the N‐terminal domain of RyR2, likely leading to a gain‐of‐function effect facilitating enhanced calcium ion release. Four generation cascade genetic and clinical screening was carried out.

Results

Thirty‐eight p.R176L variant carriers were identified of 94 family members with genetic testing, and 108 family members had clinical evaluations. Twelve carriers were symptomatic with previous syncope and 2 additional survivors of cardiac arrest were identified. Thirty‐two had clinical features suggestive of CPVT. Of 52 noncarriers, 11 had experienced previous syncope with none exhibiting any clinical features of CPVT. A documented arrhythmic event rate of 2.89/1000 person‐years across all carriers was calculated.

Conclusion

The substantial variability in phenotype and the lower than previously reported penetrance is illustrative of the importance of exploring family variants beyond first‐degree relatives.

A190 POST-PARTUM PRIMARY BILIARY CHOLANGITIS (PBC) AFTER RESOLUTION OF INTRAHEPATIC CHOLESTASIS OF PREGNANCY (ICP) IN FIRST NATION’S PATIENTS OF BC: A CASE SERIES

Background

PBC is a progressive cholestatic disease characterized by destruction of intrahepatic bile ducts, peri-portal inflammation and fibrosis. PBC is the leading indication for liver transplantation in First Nations of British Columbia. Diagnosis of PBC during pregnancy is difficult due to clinical overlap with ICP and pregnancy induced immune tolerance (4–6). We present 3 cases of clinically diagnosed ICP in First Nations women who were later diagnosed with PBC post-partum.

Aims

To investigate the potential relationship between ICP and PBC in the First Nations community of BC.

Methods

Retrospective review of relevant cases.

Results

Case 1: A 27-year-old woman with history of ICP at 31 weeks during her 3rd pregnancy and family history of PBC presented with ursodiol and cholestyramine responsive pruritis and jaundice 20 weeks into her 4th pregnancy. Bilirubin was 103 µmol/L, ALP 371 IU/L, ANA and AMA negative. Symptoms and biochemistry remained in remission after delivery at 33 weeks. Discontinuation of medications led to recurrent pruritis 4 months later. Bilirubin was 6 µmol/L, ALP 272 IU/L, GGT 153 IU/L and ALT 204 IU/L. Liver biopsy was consistent with PBC, F1. Pruritis has now been refractory to ursodiol, cholestyramine and rifampin.

Case 2: A 30-year-old woman with history of ICP at 20 weeks during 2 prior pregnancies presented with ursodiol responsive pruritis 20 weeks into her 3rd pregnancy. Symptoms and biochemistry remained in remission after delivery at 35 weeks. Post-partum discontinuation of ursodiol led to recurrent pruritis 2 months later. ALP was 876 and AMA &gt;1:640. Re-initiation of ursodiol improved symptoms and biochemical abnormalities.

Case 3: A 30-year-old woman with family history of PBC (mother) presented with ursodiol responsive pruritis and jaundice 20 weeks into her 4th pregnancy. Symptoms and biochemistry remained in remission after delivery at 37 weeks. Post-partum discontinuation of ursodiol led to recurrence jaundice 4 months later. Bilirubin was 68, ALP 1279, total cholesterol 7.72, IgM 18.98, ANA &gt;1:640 and AMA 1:320. Jaundice and biochemical abnormalities persisted despite re-initiation of ursodiol. Obeticholic acid has been initiated.

Conclusions

First Nations communities of BC are disproportionately affected by PBC, due to both genetic and epigenetic phenomena. We present 3 patients who were diagnosed with ICP that resolved post-partum but with the subsequent development of PBC. The intrapartum cholestasis did not have clinical features of PBC during pregnancy. Although not previously reported, ICP may predispose to PBC in this specific community. It remains to be seen if there is a genetic association. Clinicians must remain suspicious of PBC during pregnancy in this population and ongoing monitoring in the post-partum period is paramount.

Funding Agencies

None

Explaining the variability in cardiovascular risk factors among First Nations communities in Canada: a population-based study

BACKGROUND

Historical, colonial, and racist policies continue to influence the health of Indigenous people, and they continue to have higher rates of chronic diseases and reduced life expectancy compared with non-Indigenous people. We determined factors accounting for variations in cardiovascular risk factors among First Nations communities in Canada.

METHODS

Men and women (n=1302) aged 18 years or older from eight First Nations communities participated in a population-based study. Questionnaires, physical measures, blood samples, MRI of preclinical vascular disease, and community audits were collected. In this cross-sectional analysis, the main outcome was the INTERHEART risk score, a measure of cardiovascular risk factor burden. A multivariable model was developed to explain the variations in INTERHEART risk score among communities. The secondary outcome was MRI-detected carotid wall volume, a measure of subclinical atherosclerosis.

FINDINGS

The mean INTERHEART risk score of all communities was 17·2 (SE 0·2), and more than 85% of individuals had a risk score in the moderate to high risk range. Subclinical atherosclerosis increased significantly across risk score categories (p<0·0001). Socioeconomic advantage (-1·4 score, 95% CI -2·5 to -0·3; p=0·01), trust between neighbours (-0·7, -1·2 to -0·3; p=0·003), higher education level (-1·9, -2·9 to -0·8, p<0·001), and higher social support (-1·1, -2·0 to -0·2; p=0·02) were independently associated with a lower INTERHEART risk score; difficulty accessing routine health care (2·2, 0·3 to 4·1, p=0·02), taking prescription medication (3·5, 2·8 to 4·3; p<0·001), and inability to afford prescription medications (1·5, 0·5 to 2·6; p=0·003) were associated with a higher INTERHEART risk score. Collectively, these factors explained 28% variation in the cardiac risk score among communities. Communities with higher socioeconomic advantage and greater trust, and individuals with higher education and social support, had a lower INTERHEART risk score. Communities with difficulty accessing health care, and individuals taking or unable to afford prescription medications, had a higher INTERHEART risk score.

INTERPRETATION

Cardiac risk factors are lower in communities with high socioeconomic advantage, greater trust, social support and educational opportunities, and higher where it is difficult to access health care or afford prescription medications. Strategies to optimise the protective factors and reduce barriers to health care in First Nations communities might contribute to improved health and wellbeing.

FUNDING

Heart and Stroke Foundation of Canada, Canadian Partnership Against Cancer, Canadian Institutes for Health Research.

Bariatric surgery and the risk of congenital anomalies in subsequent pregnancies

BACKGROUND

Data on the relationship between bariatric surgery and risk of birth defects are conflicting.

OBJECTIVES

We studied the association of bariatric surgery with birth defects in future pregnancies in a large cohort of women.

METHODS

We carried out a retrospective cohort study of 2,194,348 pregnancies that occurred between 1989 and 2016 in Quebec, Canada. We identified women who had bariatric surgery before pregnancy, and included nonobese women with no surgery as a comparison group. We estimated risk ratios (RRs) and 95% CIs for the associations between bariatric surgery and the risk of birth defects, using log-binomial regression models adjusted for maternal age, comorbidities, parity, whether there was a multiple birth, socioeconomic deprivation, and the presence of folic acid food fortification.

RESULTS

In this study, 1845 deliveries were among women who had bariatric surgery before pregnancy (0.08%). Having bariatric surgery was associated with 1.20 times the risk of birth defects in later pregnancies (95% CI: 1.01, 1.43), compared with having no surgery or obesity. Obesity without having bariatric surgery was, in contrast, more weakly associated with birth defects (RR: 1.09; 95% CI: 1.07, 1.12). The association with bariatric surgery was greater for heart (RR: 1.47; 95% CI: 1.02, 2.12) and musculoskeletal defects (RR: 1.32; 95% CI: 1.02, 1.71). Associations were primarily present before folic acid food fortification was implemented (RR: 2.03; 95% CI: 1.41, 2.92), but not after (RR: 1.05; 95% CI: 0.86, 1.28).

CONCLUSIONS

Having bariatric surgery was a risk factor for birth defects, and particularly heart and musculoskeletal defects. After fortification, however, an association was no longer present. Future studies are needed to determine whether micronutrient supplementation underpins the difference in the changing results pre- and postfortification.

Future risk of cancer in women who have children with birth defects

PURPOSE

We studied whether having an infant with birth defects was associated with the risk of maternal cancer.

METHODS

We carried out a longitudinal cohort study of 1,214,506 women who delivered infants between 1989 and 2016 in Quebec, Canada. We identified women whose infants had birth defects and followed the mothers over time to identify cancers up to 28 years after delivery. We used Cox regression to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for the association between birth defects and maternal cancer, adjusted for maternal characteristics.

RESULTS

A total of 36,050 women developed cancer during 19,251,851 person-years of follow-up. Relative to no birth defects, women whose infants had defects did not have an elevated risk of cancer overall (HR 1.03, 95% CI 0.99-1.06). However, associations were present with placental cancer (HR 2.23, 95% CI 1.04-4.77) and lymphoid leukemia (HR 1.61, 95% CI 1.03-2.51). Among specific birth defects, women whose infants had heart (HR 1.12, 95% CI 1.03-1.21) or sensory (HR 1.16, 95% CI 1.04-1.30) defects had a higher risk of cancer.

CONCLUSIONS

We found inconsistent evidence of a clinically meaningful association between having an infant with birth defects and the risk of early maternal cancer.

Severe Maternal Morbidity in Canada: Temporal Trends and Regional Variations, 2003-2016

OBJECTIVE

This study sought to quantify temporal trends and provincial and territorial variations in severe maternal morbidity (SMM) in Canada.

METHODS

The study used data on all hospital deliveries in Canada (excluding Québec) from 2003 to 2016 to examine temporal trends and from 2012 to 2016 to study regional variations. SMM was identified using diagnosis and intervention codes. Contrasts among periods and regions were quantified using rate ratios (RRs) and 95% confidence intervals (CIs). Temporal changes were also assessed using chi-square tests for trend (Canadian Task Force Classification II-1).

RESULTS

The study population included 3 882 790 deliveries between 2003 and 2016 and 1 418 545 deliveries between 2012 and 2016. Severe hemorrhage rates increased from 44.8 in 2003 to 62.4 per 10 000 deliveries in 2012 (P for trend <0.0001) and then declined to 41.8 per 10 000 deliveries in 2016 (P for trend <0.0001). Maternal intensive care unit admission and sepsis rates decreased between 2003 and 2016, whereas rates of stroke, severe uterine rupture, hysterectomy, obstetric embolism, shock, and assisted ventilation increased. Rates of composite SMM in 2012-2016 were higher in Newfoundland and Labrador (RR 1.15; 95% CI 1.04-1.26), Nova Scotia (RR 1.11; 95% CI 1.03-1.19), New Brunswick (RR1.22; 95% CI 1.13-1.32), Manitoba (RR 1.09; 95% CI 1.03-1.15), Saskatchewan (RR 1.15; 95% CI 1.09-1.22), the Yukon (RR 1.74; 95% CI 1.35-2.25), and Nunavut (RR 1.76; 95% CI 1.46-2.11) compared with the rest of Canada, whereas rates were lower in Alberta and British Columbia.

CONCLUSION

This surveillance report helps inform clinical practice and public health policy for improving maternal health in Canada.

Genomic Research Through an Indigenous Lens: Understanding the Expectations

Indigenous scholars are leading initiatives to improve access to genetic and genomic research and health care based on their unique cultural contexts and within sovereign-based governance models created and accepted by their peoples. In the past, Indigenous peoples' engagement with genomicresearch was hampered by a lack of standardized guidelines and institutional partnerships, resulting in group harms. This article provides a comparative analysis of research guidelines from Canada, New Zealand, Australia, and the United States that pertain to Indigenous peoples. The goals of the analysis are to identify areas that need attention, support Indigenous-led governance, and promote the development of a model research policy framework for genomic research and health care that has international relevance for Indigenous peoples.

Prepregnancy asthma and the subsequent risk of central nervous system defects in offspring

BACKGROUND

The relationship between childhood asthma and central nervous system defects in offspring is poorly understood. We assessed if childhood asthma was associated with the risk of having an infant with neural tube or other nervous system defects compared with asthma during pregnancy.

METHODS

We analyzed a longitudinal cohort of 128,060 women who were 5 years or less at study entry and later delivered an infant in Quebec, Canada (1989-2014). We identified women hospitalized for asthma before pregnancy, including childhood and adolescence, and determined if asthma was present during pregnancy based on obstetric records. Main outcomes were neural tube and non-neural tube defects in pregnancy. We used log-binomial regression models to determine risk ratios (RR) and 95% confidence intervals (CI) for the association between asthma and risk of nervous system defects, adjusting for patient characteristics.

RESULTS

Asthma was associated with a greater risk of neural tube defects in offspring (RR 2.39, 95% CI 1.03-5.53) compared with no asthma, but not non-neural tube defects (RR 1.10, 95% CI 0.71-1.71). Women whose asthma resolved before pregnancy had a greater risk of neural tube defects (RR 3.43, 95% CI 1.35-8.69), while women with asthma during pregnancy were at greater risk of non-neural tube defects, especially microcephaly (RR 2.80, 95% CI 1.23-6.40).

CONCLUSIONS

Asthma that resolved before pregnancy was associated with an increased risk of neural tube defects in offspring but not non-neural tube defects. Further investigation is needed to determine the pathophysiology connecting childhood asthma with nervous system defects in offspring.

The p.P479L variant in CPT1A is associated with infectious disease in a BC First Nation

Background

The hepatic carnitine palmitoyltransferase I (CPT1A) p.P479L variant is common in Aboriginal populations across coastal British Columbia, Alaska, the Canadian North, and Greenland. While the high frequency of this variant suggests positive selection, other studies have shown an association with sudden unexpected death in infancy and infection. We utilized administrative health data to evaluate hospitalizations for a single year cohort of children of First Nations descent genotyped for the variant and, matched for location of birth. Seven years of data were reviewed for 150 children split evenly between CPT1A genotypes (homozyous, heterozygous, and noncarrier of the p.P479L variant).

Results

Children homozygous for the p.P479L allele had a higher rate of hospital admissions at 2.6 per individual as compared to noncarriers at 0.86. Heterozygous children also showed a significant increase at 1.9 per person. Length of stay per admission was increased for both p.P479L homozygotes and heterozygotes. The odds ratio (OR) for at least one hospitalization for any reason was increased for p.P479L homozygotes relative to noncarriers (OR=10.2, confidence interval [CI] 3.5 to 30.0) as were admissions for dental caries (OR=3.4, CI 1.5 to 7.8), acute lower respiratory tract infections (OR=6.0, CI 1.6 to 22.4), and otitis media (OR=13.5, CI 1.7 to 109.4).

Conclusions

The CPT1A p.P479L variant is associated with an increased rate of hospitalization for those homozygous, primarily for infectious disease causes. Heterozygotes also showed a small but significant increase in hospitalization rates suggesting some dosage effect. Functional studies will be required to identify the underlying pathological mechanism.

Risk of central nervous system defects in offspring of women with and without mental illness

We sought to determine the relationship between maternal mental illness and the risk of having an infant with a central nervous system defect. We analyzed a cohort of 654,882 women aged less than 20 years between 1989 and 2013 who later delivered a live born infant in any hospital in Quebec, Canada. The primary exposure was mental illness during pregnancy or hospitalization for mental illness before pregnancy. The outcomes were neural and non-neural tube defects of the central nervous system in any offspring. We computed risk ratios (RR) and 95% confidence intervals (CI) for the association between mental disorders and risk of central nervous system defects in log-binomial regression models adjusted for age at delivery, total parity, comorbidity, socioeconomic deprivation, place of residence, and time period. Maternal mental illness was associated with an increased risk of nervous system defects in offspring (RR 1.76, 95% CI 1.64-1.89). Hospitalization for any mental disorder was more strongly associated with non-neural tube (RR 1.84, 95% CI 1.71-1.99) than neural tube defects (RR 1.31, 95% CI 1.08-1.59). Women at greater risk of nervous system defects in offspring tended to be diagnosed with multiple mental disorders, have more than one hospitalization for mental disease, or be 17 or older at first hospitalization. A history of mental illness is associated with central nervous system defects in offspring. Women hospitalized for mental illness may merit counseling at first symptoms to prevent central nervous system defects at pregnancy.

Exome sequencing identified a de novo mutation of PURA gene in a patient with familial Xp22.31 microduplication

The clinical significance of Xp22.31 microduplication is controversial as it is reported in subjects with developmental delay (DD), their unaffected relatives and unrelated controls. We performed multifaceted studies in a family of a boy with hypotonia, dysmorphic features and DD who carried a 600 Kb Xp22.31 microduplication (7515787-8123310bp, hg19) containing two genes, VCX and PNPLA4. The duplication was transmitted from his cognitively normal maternal grandfather. We found no evidence of the duplication causing the proband's DD and congenital anomalies based on unaltered expression of PNPLA4 in the proband and his mother in comparison to controls and preferential activation of the paternal chromosome X with Xp22.31 duplication in proband's mother. However, a de novo, previously reported deleterious, missense mutation in Pur-alpha gene (PURA) (5q31.2), with a role in neuronal differentiation was detected in the proband by exome sequencing. We propose that the variability in the phenotype in carriers of Xp22.31 microduplication can be due to a second and more deleterious genetic mutation in more severely affected carriers. Widespread use of whole genome next generation sequencing in families with Xp22.31 CNV could help identify such cases.

Primary Biliary Cholangitis in British Columbia First Nations: Clinical features and discovery of novel genetic susceptibility loci

BACKGROUND & AIMS

Primary Biliary Cholangitis (PBC) is a chronic autoimmune liver disease characterized by destruction of intrahepatic bile ducts, portal inflammation and cirrhosis. Although rare in most populations, it is prevalent and often familial in British Columbia First Nations. We hypothesized that major genetic factors increased the risk in First Nations.

METHODS

In all, 44 individuals with Primary Biliary Cholangitis and 61 unaffected relatives from 32 First Nations families participated. Family history and co-morbidities were documented. Medical records were reviewed and available biopsies were re-reviewed by our team pathologist. Genotyping was performed on DNA from 36 affected persons and 27 unaffected relatives using the Affymetrix Human Mapping 500K Array Set. MERLIN software was used to carry out multipoint parametric and nonparametric linkage analysis. Candidate genes were identified and entered into InnateDB and KEGG software to identify potential pathways affecting pathogenesis.

RESULTS

In all, 34% of families were multiplex. Fifty per cent of cases and 33% of unaffected relatives reported other autoimmune disease. Three genomic regions (9q21, 17p13 and 19p13) produced LOD scores of 2.3 or greater suggestive of linkage, but no single linkage peak reached statistical significance. Candidate genes identified in the three regions suggested involvement of IL17, NFκB, IL6, JAK-STAT, IFNγ and TGFβ immune signalling pathways. Specifically, four genes-ACT1, PIN1, DNMT1 and NTN1-emerged as having roles in these pathways that may influence Primary Biliary Cholangitis pathogenesis.

CONCLUSIONS

Our whole genome linkage study results reflect the multifactorial nature of Primary Biliary Cholangitis, support previous studies suggesting signalling pathway involvement and identify new candidate genes for consideration.

Congenital microcephaly in Quebec: baseline prevalence, risk factors and outcomes in a large cohort of neonates

OBJECTIVE

We assessed baseline prevalence, risk factors and outcomes of microcephaly in a large population of neonates.

DESIGN

Retrospective cohort study.

SETTING

All hospitals in the province of Quebec, Canada.

PARTICIPANTS

794 microcephalic and 1 944 010 non-microcephalic infants born between 1989 and 2012.

MAIN OUTCOME MEASURES

Baseline prevalence of microcephaly and occurrence of other congenital anomalies. We estimated the association of (1) pregnancy risk factors including TORCH infections (toxoplasmosis, rubella, cytomegalovirus, herpes, other), exposure to teratogens, diabetes and maternal congenital anomalies with risk of microcephaly, and (2) microcephaly with risk of infant mortality and severe morbidity, adjusted for maternal characteristics.

RESULTS

The overall prevalence of microcephaly was 4.1 per 10 000, ranging between 3.0 and 5.3 per 10 000 over time. Only 37% of microcephalic infants presented with other congenital anomalies. Maternal infection during pregnancy was the strongest risk factor, with 32 times the risk of microcephaly (prevalence ratio 32.38; 95% CI 22.42 to 46.75) compared with no infection. Exposure to teratogens was the next most important risk factor, with three times greater risk (prevalence ratio 3.10; 95% CI 2.37 to 4.07). Microcephaly was associated with 20 times the risk of infant mortality compared with no microcephaly (prevalence ratio 20.52; 95% CI 15.57 to 27.04) and significantly greater infant morbidity.

CONCLUSIONS

In Canada, infectious exposure during pregnancy is a strong risk factor for microcephaly, and affected infants are at higher risk of poor birth outcomes. Better monitoring of microcephaly is needed in the event that Zika or other novel viruses affect future risk.