An inventory of Canadian pregnancy and birth cohort studies: research in progress

Worldwide cohort studies to support healthy ageing research: data availabilities and gaps

BACKGROUND

Population ageing is a transforming demographic force. To support evidence-based efforts for promoting healthy ageing, a summary of data availabilities and gaps to study ageing is needed.

METHOD

Through a multifaceted search strategy, we identified relevant cohort studies worldwide to studying ageing and provided a summary of available pertinent measurements. Following the World Health Organization's definition of healthy ageing, we extracted information on intrinsic capacity domains and sociodemographic, social, and environmental factors.

RESULTS

We identified 287 cohort studies. South America, the Middle East, and Africa had a limited number of cohort studies to study ageing compared to Europe, Oceania, Asia, and North America. Data availabilities of different measures varied substantially by location and study aim. Using the information collected, we developed a web-based Healthy Ageing Toolkit to facilitate healthy ageing research.

CONCLUSIONS

The comprehensive summary of data availability enables timely evidence to contribute to the United Nations Decades of Healthy Ageing goals of promoting healthy ageing for all. Highlighted gaps guide strategies for increased data collection in regions with limited cohort studies. Comprehensive data, encompassing intrinsic capacity and various sociodemographic, social, and environmental factors, is crucial for advancing our understanding of healthy ageing and its underlying pathways.

Six decades of longitudinal health knowledge production: a systematic review on Nordic birth cohort studies

This systematic review (a) identifies birth cohort studies (BCSs) established in the Nordic countries, (b) describes their basic characteristics, and (c) explores how these characteristics have evolved over time, discussing their implications to knowledge production. To identify Nordic BCSs, cohort databases and relevant scientific articles were systematically searched and screened.The review shows that since 1959, more than 600,000 index children have participated in the 79 Nordic BCSs (22 Danish, 20 Finnish, 12 Norwegian, 24 Swedish, one Icelandic), over half of them still ongoing. The Nordic BCSs cover a wide geographical area including the Nordic Arctic. The topics of BCSs have varied over time but most have focused on examining the developmental origins of diseases. A quarter of them had a general scope, while the rest started with a specific focus, commonly atopic diseases. All BCSs collected questionnaire and/or interview data and over 60% of the BCSs announced exclusion criteria for participants, typically insufficient language proficiency.NBCSs have produced crucial scientific knowledge for over six decades, but there are underutilised opportunities including systematic interdisciplinary collaboration, inclusion of children's own views of their health and well-being, intergenerational data collection, and specific knowledge of Arctic indigenous peoples and other minorities.

An Inventory of European Birth Cohorts

Many birth cohorts have been carried out. We performed a review of European birth cohorts to see the countries involved, provide a panorama of the current research topics and design, and, more generally, provide input for those creating collaborations and laying out guidelines aimed at unifying cohort methodologies to enable data merging and maximize knowledge acquisition. We searched PubMed and Embase for articles referring to longitudinal, prospective European birth cohorts and searched online cohort inventories. We found references to 111 birth cohorts, 45 of which began enrolment at birth. These cohorts began between 1921 and 2015 and represented 19 countries, with varying sample sizes (236 to 21,000 children). As of 5 January 2020, were still recruiting. The main areas addressed were allergic diseases (14 cohorts) and environmental exposure (f12 cohorts) and most cohorts were publicly funded. Given the large costs of running cohorts and the importance of long follow-up periods in identifying the risk factors for disorders thought to have a perinatal/early life etiology, current cohorts must be designed to answer research questions considering several aspects, from genetic ones to psychological, social, and environmental ones. Furthermore, universally recognized methodological aspects are needed to permit the comparison and merging of cohort data.

Methods for the assessment of selection bias in drug safety during pregnancy studies using electronic medical data

Electronic health data are routinely used for population drug studies. Due to the ethical dilemma in carrying out experimental drug studies on pregnant women, the effects of medication usage during pregnancy on fetal and maternal outcomes are largely evaluated using this data collection medium. One major limitation in this type of study is the delayed inclusion of pregnancies in the cohort. For example, in the province of Quebec, Canada, a major pregnancy cohort only captured pregnancies after 20 weeks gestation. The purpose of this study was to demonstrate three methods that can be used to assess the extent of selection bias due to the delayed inclusion of pregnancies. We use causal directed acyclic graphs to explain the source of this selection bias. In an example involving a cohort of pregnant asthmatic women reconstructed from the linkage of administrative health databases from the province of Quebec, we use numerical derivations, a simulation study and a sensitivity analysis to investigate the potential for bias and loss of power due to the delayed inclusion. We find that this selection bias can be partially mitigated by controlling for variables related to (spontaneous or therapeutic) abortion and the outcome of interest. The three proposed methods allow for the pre and post hoc ascertainment of the bias. While delayed pregnancy inclusion selection bias (which includes "live birth bias") can produce substantial bias in pregnancy drug studies, all three methods are effective at producing estimates of the size of the bias.

Healthy Foundations Study: a randomised controlled trial to evaluate biological embedding of early-life experiences

INTRODUCTION

Adverse early experiences are associated with long-lasting disruptions in physiology, development and health. These experiences may be 'biologically embedded' into molecular and genomic systems that determine later expressions of vulnerability. Most studies to date have not examined whether preventive interventions can potentially reverse biological embedding. The Nurse-Family Partnership (NFP) is an evidence-based intervention with demonstrated efficacy in improving prenatal health, parenting and child functioning. The Healthy Foundations Study is an innovative birth cohort which will evaluate the impact of the NFP on biological outcomes of mothers and their infants.

METHODS AND ANALYSIS

Starting in 2013, up to 400 pregnant mothers and their newborns were recruited from the British Columbia Healthy Connections Project-a randomised controlled trial of the NFP, and will be followed to child aged 2 years. Women were recruited prior to 28 weeks' gestation and then individually randomised to receive existing services (comparison group) or NFP plus existing services (intervention group). Hair samples are collected from mothers at baseline and 2 months post partum to measure physiological stress. Saliva samples are collected from infants during all visits for analyses of stress and immune function. Buccal swabs are collected from infants at 2 and 24 months to assess DNA methylation. Biological samples will be related to child outcome measures at age 2 years.

ETHICS AND DISSEMINATION

The study received ethical approval from seven research ethics boards. Findings from this study will be shared broadly with the research community through peer-reviewed publications, and conference presentations, as well as seminars with our policy partners and relevant healthcare providers. The outcomes of this study will provide all stakeholders with important information regarding how early adversity may lead to health and behavioural disparities and how these may be altered through early interventions.

TRIAL REGISTRATION NUMBER

NCT01672060; Pre-results.

Generation and validation of a universal perinatal database and biospecimen repository: PeriBank

OBJECTIVE

There is a dearth of biospecimen repositories available to perinatal researchers. In order to address this need, here we describe the methodology used to establish such a resource.

STUDY DESIGN

With the collaboration of MedSci.net, we generated an online perinatal database with 847 fields of clinical information. Simultaneously, we established a biospecimen repository of the same clinical participants.

RESULTS

The demographic and clinical outcomes data are described for the first 10 000 participants enrolled. The demographic characteristics are consistent with the demographics of the delivery hospitals. Quality analysis of the biospecimens reveals variation in very few analytes. Furthermore, since the creation of PeriBank, we have demonstrated validity of the database and tissue integrity of the biospecimen repository.

CONCLUSION

Here we establish that the creation of a universal perinatal database and biospecimen collection is not only possible, but allows for the performance of state-of-the-science translational perinatal research and is a potentially valuable resource to academic perinatal researchers.

The Canadian Healthy Infant Longitudinal Development (CHILD) Study: examining developmental origins of allergy and asthma

The Canadian Healthy Infant Longitudinal Development (CHILD) birth cohort study recruited 3624 pregnant women, most partners and 3542 eligible offspring. We hypothesise that early life physical and psychosocial environments, immunological, physiological, nutritional, hormonal and metabolic influences interact with genetics influencing allergic diseases, including asthma. Environmental and biological sampling, innate and adaptive immune responses, gene expression, DNA methylation, gut microbiome and nutrition studies complement repeated environmental and clinical assessments to age 5. This rich data set, linking prenatal and postnatal environments, diverse biological samples and rigorous phenotyping, will inform early developmental pathways to allergy, asthma and other chronic inflammatory diseases.