Longitudinal Intergenerational Birth Cohort Designs: A Systematic Review of Australian and New Zealand Studies

Ethnic-specific characteristics associated with longitudinal response patterns from prebirth to 12 years: evidence from Growing Up in New Zealand

BACKGROUND

Longitudinal studies can generate valuable scientific knowledge, but can be compromised by systematic attrition. Previous research shows that sociodemographic characteristics (eg, ethnicity, age, educational level, socioeconomic circumstances) are associated with attrition rates. However, little is known about whether these characteristics differ by ethnicity, and how this impacts cohort retention strategies.

METHODS

Using antenatal to 12-year data from the Growing Up in New Zealand birth cohort study (N=6743), we examined transversal response rates by ethnicity (Māori, Pacific, Asian, European), used sequence analysis and cluster analysis to identify unique longitudinal response patterns, and binary logistic regression to examine ethnic-specific sociodemographic characteristics associated with these response patterns.

RESULTS

The overall response rate at 12 years was 71.0%, with ethnic differences in response rates widening over the six data collection waves. Three longitudinal response patterns were identified: frequent responders (65.2%), intermittent non-responders (29.6%) and frequent non-responders (5.2%). Sociodemographic characteristics such as younger maternal age and lower maternal education were associated with a higher likelihood of membership in the non-response clusters across all ethnic groups. However, there were also important nuances by ethnicity. Individual level factors (eg, household material deprivation and maternal general health) tended to be associated with non-response for Europeans, whereas structural level factors (eg, area-level deprivation and racial discrimination) tended to be associated with non-response for Māori, Pacific and Asian peoples.

CONCLUSION

Ethnic differences in longitudinal response patterns are due to multiple factors of disadvantage, and therefore require targeted retention strategies. Stratifying analyses by ethnicity is important for revealing nuanced insights.

Nepal Family Cohort study: a study protocol

INTRODUCTION

The Nepal Family Cohort study uses a life course epidemiological approach to collect comprehensive data on children's and their parents' environmental, behavioural and metabolic risk factors. These factors can affect the overall development of children to adulthood and the onset of specific diseases. Among the many risk factors, exposure to air pollution and lifestyle factors during childhood may impact lung development and function, leading to the early onset of respiratory diseases. The global incidence and prevalence of respiratory diseases are rapidly increasing, with the rate of increase in Nepal being the highest. Although the cohort will primarily focus on respiratory health, other health outcomes such as cardiovascular, metabolic and mental health will be assessed to provide a comprehensive overall health assessment. All other health outcomes are self-reported following doctor diagnosis. Some of these health outcomes will be quality controlled during the follow-up by measuring disease specific markers. Our cohort study will likely provide evidence of risk factors and policy recommendations.

METHODS AND ANALYSIS

Using a life-course epidemiology approach, we established a longitudinal study to address the determinants of lung health and other health outcomes from childhood to adulthood. The baseline data collection (personal data anonymised) was completed in April 2024, and 16 826 participants (9225 children and 7601 parents) from 5829 families were recruited in different geographical and climate areas (hills and plains) of Nepal. We plan to follow up all the participants every 2-3 years.Descriptive analysis will be used to report demographic characteristics and compare rural and semi-urban regions. A linear regression model will assess the association between air pollution, particularly household air pollution (HAP) exposure, and other lifestyle factors, with lung function adjusted for potential confounders. A two-stage linear regression model will help to evaluate lung development based on exposure to HAP.

ETHICS

Ethical approval was obtained from the Nepal Health Research Council, Kathmandu, Nepal, and McMaster University, Hamilton, Canada. Permissions were obtained from two municipalities where the study sites are located. Parents provided signed informed consent and children their assent.

DISSEMINATION

Findings will be disseminated through traditional academic pathways, including peer-reviewed publications and conference presentations. We will also engage the study population and local media (ie, research blogs and dissemination events) and prepare research and policy briefings for stakeholders and leaders at the local, provincial and national levels.

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.

Newcastle 1000 (NEW1000) Study: an Australian population-based prospective pregnancy cohort study design and protocol

INTRODUCTION

Multiple cohort studies have been established to investigate the impact of early life factors on development and health outcomes. In Australia the majority of these studies were established more than 20 years ago and, although longitudinal in nature, are inherently susceptible to socioeconomic, environmental and cultural influences which change over time. Additionally, rapid leaps in technology have increased our understanding of the complex role of gene-environment interactions in life course health, highlighting the need for new cohort studies with repeated biological sampling and in-depth phenotype data across the first 1000 days of life from conception.

METHODS AND ANALYSIS

The Newcastle 1000 (NEW1000) Study, based in the regional city of Newcastle, New South Wales, was developed after an extensive consultation process involving 3 years of discussion with key stakeholders and healthcare consumer organisations and seven healthcare consumer workshops. This prospective population-based pregnancy cohort study will recruit 500 families per year for 5 years, providing detailed, longitudinal, multisystem phenotyping, repeated ultrasound measures and serial sample collection to investigate healthcare consumer identified health outcomes of priority. Stage 1 will involve recruitment of pregnant participants and their partners at 14 weeks gestation, with dense phenotype data and biological samples collected at 14, 20, 28 and 36 weeks gestation and serial ultrasound measures at 20, 28, 36 and 40 weeks, with postpartum follow-up at 6 weeks and 6 months. Biological samples will be used for biomarker discovery and sequencing of the genome, transcriptome, epigenome, microbiome and metabolome.

ETHICS AND DISSEMINATION

Ethics approval was obtained from Hunter New England Local Health District Ethics Committee (2020/ETH02881). Outcomes will be published in peer-reviewed journals, disseminated to participants through the NEW1000 website, presented at scientific conferences, and written reports to local, state and national government bodies and key stakeholders in the healthcare system to inform policy and evidence-based practice.

Birth cohort studies using symptom diaries for assessing respiratory diseases–a scoping review

Background

Respiratory infections are the most frequent health problem in childhood leading to morbidity and socioeconomic burden. Studying symptoms of respiratory infections in home based settings requires dedicated prospective cohort studies using diaries. However, no information is available on which birth cohort studies using symptom diary data. A review of birth cohort studies with available symptom diary data, follow-up data, and bio samples is needed to support research collaborations and create potential synergies.

Methods

We conducted a scoping review of birth cohort studies using diaries for the collection of respiratory symptoms. The scoping review was conducted in accordance with the PRISMA Extension. We searched the electronic databases PubMed, Embase, Web of science and CINAHL (last search November 2020) resulting in 5872 records (based on title and abstract screening) eligible for further screening.

Results

We examined 735 records as full text articles and finally included 57 according to predefined inclusion criteria. We identified 22 birth cohort studies that collect(ed) data on respiratory symptoms using a symptom diary starting at birth. Numbers of participants ranged from 129 to 8677. Eight studies collected symptom diary information only for the first year of life, nine for the first two years or less and six between three and six years. Most of the cohorts collected biosamples (n = 18) and information on environmental exposures (n = 19).

Conclusion

Information on respiratory symptoms with daily resolution was collected in several birth cohorts, often including related biosamples, and these data and samples can be used to study full spectrum of infections, particularly including those which did not require medical treatment.

Early magnetic resonance imaging biomarkers of schizophrenia spectrum disorders: Toward a fetal imaging perspective

There is mounting evidence to implicate the intrauterine environment as the initial pathogenic stage for neuropsychiatric disease. Recent developments in magnetic resonance imaging technology are making a multimodal analysis of the fetal central nervous system a reality, allowing analysis of structural and functional parameters. Exposures to a range of pertinent risk factors whether preconception or in utero can now be indexed using imaging techniques within the fetus' physiological environment. This approach may determine the first "hit" required for diseases that do not become clinically manifest until adulthood, and which only have subtle clinical markers during childhood and adolescence. A robust characterization of a "multi-hit" hypothesis may necessitate a longitudinal birth cohort; within this investigative paradigm, the full range of genetic and environmental risk factors can be assessed for their impact on the early developing brain. This will lay the foundation for the identification of novel biomarkers and the ability to devise methods for early risk stratification and disease prevention. However, these early markers must be followed over time: first, to account for neural plasticity, and second, to assess the effects of postnatal exposures that continue to drive the individual toward disease. We explore these issues using the schizophrenia spectrum disorders as an illustrative paradigm. However, given the potential richness of fetal magnetic resonance imaging, and the likely overlap of biomarkers, these concepts may extend to a range of neuropsychiatric conditions.

Queensland Family Cohort: a study protocol

INTRODUCTION

The perinatal-postnatal family environment is associated with childhood outcomes including impacts on physical and mental health and educational attainment. Family longitudinal cohort studies collect in-depth data that can capture the influence of an era on family lifestyle, mental health, chronic disease, education and financial stability to enable identification of gaps in society and provide the evidence for changes in government in policy and practice.

METHODS AND ANALYSIS

The Queensland Family Cohort (QFC) is a prospective, observational, longitudinal study that will recruit 12 500 pregnant families across the state of Queensland (QLD), Australia and intends to follow-up families and children for three decades. To identify the immediate and future health requirements of the QLD population; pregnant participants and their partners will be enrolled by 24 weeks of gestation and followed up at 24, 28 and 36 weeks of gestation, during delivery, on-ward, 6 weeks postpartum and then every 12 months where questionnaires, biological samples and physical measures will be collected from parents and children. To examine the impact of environmental exposures on families, data related to environmental pollution, household pollution and employment exposures will be linked to pregnancy and health outcomes. Where feasible, data linkage of state and federal government databases will be used to follow the participants long term. Biological samples will be stored long term for future discoveries of biomarkers of health and disease.

ETHICS AND DISSEMINATION

Ethical approval has been obtained from the Mater Research Ethics (HREC/16/MHS/113). Findings will be reported to (1) QFC participating families; (2) funding bodies, institutes and hospitals supporting the QFC; (3) federal, state and local governments to inform policy; (4) presented at local, national and international conferences and (5) disseminated by peer-review publications.

The growth and development of cohort studies

Cohort studies are special forms of longitudinal studies that have long been accepted as the primary designs to acquire information on the interaction between the environment and health and the subsequent aetiology and progression of disease. Richard Doll, Regius Professor of Medicine at Oxford University from 1969-1979, was the 20th century's pre-eminent epidemiologist in the UK. He used cohort studies to establish the relationship between smoking and health (primarily cancer) in the 1960s at a time when over 80% of British males smoked. However, the development of cohorts as a means of studying health and wellbeing across the lifespan is rooted in research on tuberculosis in Europe and America in the 1920s and 1930s. Cohort studies were recognised as the primary research design for the study of human growth and development between and during the wars in the USA. Their natural legacy as longitudinal studies emerged in Europe after WWII through a series of growth studies coordinated by the Centre Internationale de L'Enfance in Paris from the 1960s onwards. The failure of two nationally representative birth cohort studies in the USA and UK between 2010 and 2015 has highlighted the previous success of smaller birth cohorts and the advantages gained from standardised methods of measurement and assessment that allow amalgamation and metanalysis of different datasets.

Parent-reported birth information: birth weight, birth length and gestational age. Validation study in the SENDO project

OBJECTIVE

To test the validity of parent-reported birth information obtained through an online, self-administered questionnaire.

METHOD

The SENDO project is a prospective and dynamic paediatric cohort of Spanish children aged 4 to 6 years old at recruitment. Objective data from medical birth records were compared to parent-reported data getting intra-class correlation coefficients (ICC) for quantitative variables and weighted Kappa Index for qualitative ones. Percentage of responders and of total agreement was also evaluated.

RESULTS

Parental response rate was over 99% for birth weight and gestational age and 76% for birth length. ICC for birth weight was 0.95 (95% confidence interval [95%CI]: 0.94-0.96) and 0.78 (95%CI: 0.73-0.83) for birth length, both showing very high correlations. The total agreement percentage for gestational age was 97%, and Kappa weighted index was 0.90 (95%CI: 0.89-0.90), showing a very high agreement as well.

CONCLUSIONS

We found high correlations and excellent agreement in parent-reported birth data 4 to 6 years after delivery. Our results show parent-reported birth data, especially birth weight, are valid for use in epidemiological research.

A systemic review of maternal wellbeing and its relationship with maternal fetal attachment and early postpartum bonding

BACKGROUND

An emerging body of literature suggests there is a relationship between a pregnant woman's psychological wellbeing and the development of maternal-fetal attachment (MFA) and early postpartum bonding. The nature of this relationship is not well understood because of the limited theoretical framework surrounding the construct of MFA and variations in study methods and data collection points. In this systematic review, we synthesize the published literature to determine the nature of the relationship from the antenatal to early postnatal period and to provide recommendations for future research and clinical practice.

METHOD

Using the preferred reporting items for systematic reviews and meta-analyses (PRISMA) approach, four electronic databases were searched for peer-reviewed empirical studies, published in English. Articles were considered for inclusion if data was collected on at least one domain of maternal wellbeing/mental health and MFA during pregnancy or MFA during pregnancy and the mother-infant relationship during the early postpartum period (up to 12 weeks). No date parameters were applied to the search strategy. The review was registered with PROPSERO (registration number: CRD42018096174).

RESULTS

25 studies examining maternal mental health and MFA/postpartum bonding were selected for inclusion in this review. Key findings identified from the review were: a need to validate existing mental health measures or develop new measures specific for use in antenatal populations; inconsistencies in data collection points throughout pregnancy and postpartum; a lack of consensus about the construct of MFA and the way it is assessed; and a continued focus on postpartum outcomes.

CONCLUSION

Scientific gaps remain in our understanding of the relationship between maternal mental health and both MFA and postpartum bonding which limit our theoretical understanding of the MFA construct. Recommendations for future research are to employ prospective longitudinal designs that span the full pregnancy and postpartum period, and for consistency in the terminology and methodology used when considering MFA. A re-focus of research attention on the theory behind MFA will allow a richer and more holistic account of the emerging relationship between mother and baby.

Illawarra Born cross-generational health study: feasibility of a multi-generational birth cohort study

Background

There is a strong interest in the concept of developmental origins of health and disease and their influence on various factors “from cradle to grave”. Despite the increasing appreciation of this lifelong legacy across the human life course, many gaps remain in the scientific understanding of mechanisms influencing these formative phases. Cross-generational susceptibility to health problems is emerging as a focus of research in the context of birth cohort studies.

The primary aim of the Illawarra Born study is to make scientific discoveries associated with improving health and wellbeing across the lifespan, with a particular focus on preventable chronic diseases, especially mental health. This birth cohort study will follow and collect data from three cohorts representing different stages across the lifespan: infants, adults (parents) and older adults (grandparents). The multi-generational, cross-sectional and longitudinal design of this birth cohort study supports a focus on the contributions of genetics, environment and lifestyle on health and wellbeing. The feasibility of conducting a multi-generational longitudinal birth cohort project was conducted through a small pilot study.

Methods/design

The purpose of this paper is to report on the feasibility and acceptability of the research protocol for a collaborative cross-generation health study in the community and test recruitment and outcome measures for the main study. This feasibility study included pregnant women who were intending to give birth in the Illawarra-Shoalhaven region in Eastern Australia. The area includes a large, regional referral hospital, with capacity to treat specialist and complex cases. Pregnant women were asked to participate in five data collection waves beginning at 22 weeks gestation and ending with a 6-month post-partum appointment. Recruitment was then extended, via the pregnant women, to also include fathers and maternal grandmothers.

Discussion

This feasibility study focused on the perinatal period and collected data across three multi-disciplinary domains including mental health, diet, exposures to toxins and the role of these in maternal and infant outcomes. Forty-one families participated in extensive data collection from 22 weeks gestation to 6-months post-partum. Factors impacting on viability and feasibility including recruitment solutions provide the basis for a large-scale study.

Stop, think, reflect, realize-first-time mothers' views on taking part in longitudinal maternal health research

Background

Longitudinal cohort studies gather large amounts of data over time, often without direct benefit to participants. A positive experience may encourage retention in the study, and participants may benefit in unanticipated ways.

Objective

To explore first‐time mothers’ experiences of taking part in a longitudinal cohort study and completing self‐administered surveys during pregnancy and at 3, 6, 9 and 12 months’ postpartum.

Design

Content analysis of comments written by participants in the Maternal health And Maternal Morbidity in Ireland study's five self‐completion surveys, a multisite cohort study exploring women's health and health problems during and after pregnancy. This paper focuses on what women wrote about taking part in the research. Ethical approval was granted by the site hospitals and university.

Setting and participants

A total of 2174 women were recruited from two maternity hospitals in Ireland between 2012 and 2015.

Findings

A total of 1000 comments were made in the five surveys. Antenatally, barriers related to surveys being long and questions being intimate. Postpartum, barriers related to being busy with life as first‐time mothers. Benefits gained included gaining access to information, taking time to reflect, stopping to think and being prompted to seek help. Survey questions alone were described as valuable sources of information.

Discussion and conclusions

Findings suggest that survey research can “give back” to women by being a source of information and a trigger to seek professional help, even while asking sensitive questions. Understanding this can help researchers construct surveys to maximize benefits, real and potential, for participants.

Occurrence of 44 elements in human cord blood and their association with growth indicators in newborns

There is growing concern about environmental pollution produced by elements, including "emerging" contaminants, such as rare earth elements (REE) and other trace elements (TE), which are extensively and increasingly employed in the manufacture of consumer electronics. Previous research has shown that prenatal exposure to some elements (mainly heavy metals) may be associated with decreased fetal growth and other adverse birth outcomes. Recent studies have also shown that environmental exposure to REE and TE may be related to adverse effects on human health. This cross-sectional study, which included nearly 92% of the births in 2016 in La Palma (Canary Islands, Spain; n = 471), aimed to evaluate the potential adverse health effects exerted by a wide range of elements on newborns. We quantified the levels of 44 elements (including 26 REE and TE) in their umbilical cord blood. Our results showed low or very low levels of most elements. We found an inverse association between antimony (Sb) and birth weight (Spearman's r = -0.106, p = 0.021). A similar trend was observed between nickel (Ni) and birth weight and between chromium (Cr) and birth length, although in this case the significance was borderline. Bismuth appeared as a risk factor for having a birth weight below the tenth percentile in the univariate (OR = 3.30; 95% CI = 1.25-8.78; p = 0.017) and multivariate analyses (OR = 5.20; 95% CI = 1.29-20.91; p = 0.020). When assessing the effect of element mixtures, the sum of Cr, Ni, and Sb appeared as a risk factor for having a birth weight below the tenth percentile in the univariate (OR = 2.41; 95% CI = 1.08-5.35; p = 0.031) and multivariate analyses (OR = 3.84; 95% CI = 1.42-10.39; p = 0.008). Our findings suggest that some inorganic elements-isolated or in mixture-are associated to a lower fetal growth. Additional research is needed to understand the role of inorganic pollutants on fetal development.

Epidemiology of Pediatric Critical Illness in a Population-Based Birth Cohort in Olmsted County, MN

OBJECTIVES

Investigations of pediatric critical illness typically focus on inpatient cohorts drawn from wide referral areas and diverse healthcare systems. Cohorts amenable to investigating the full spectrum of critical illness as it develops within a community have yet to be studied in the United States. Our objective was to provide the first epidemiologic report of the incidence and presentation of pediatric critical illness within a U.S. population-based birth cohort.

DESIGN

Retrospective cohort study.

SETTING

A geographically defined community (Olmsted, MN) with medical record linkage across all health systems. All ICU services are provided within a single children's hospital.

PATIENTS

A birth cohort of children (n =9,441) born 2003-2007 in Olmsted County, MN.

MEASUREMENTS AND MAIN RESULTS

During the study period, there were a total of 15,277 ICU admissions to Mayo Clinic Children's Hospital. A total of 577 birth cohort children accounted for 824 of these admissions during the 61,770 person-years of follow-up accumulated. Incidence of first-time ICU admission was 9.3 admits per 1,000 person-years. Admission rates were highest in the first year of life and then declined steadily. Respiratory problems were among the most common reasons for admission at any age and diagnoses reflect changes in health risk factors as children grow and develop over time. After 1 year old, a majority of children admitted have preexisting chronic comorbidities and/or prior ICU stays. In-hospital mortality occurred exclusively in children admitted prior to 5 days of age (n = 4). Seven children died after hospital discharge.

CONCLUSIONS

This is the first report characterizing critical illness within a population-based birth cohort of U.S. children. The results demonstrate the changing incidence, presentation, and healthcare requirements associated with critical illness across the developmental spectrum as a population of children ages.