Born in Bradford (BiB) is a prospective pregnancy and birth cohort study based in Bradford, United Kingdom (UK). The study was established in 2007 to examine how genetic, nutritional, environmental, behavioural and social factors affect health and development during childhood, and subsequently, adult life in a deprived multi-ethnic population. Now that children have reached age 7–11 years, BiB is revisiting study families in the first full follow-up of the cohort [1, 2]. This is exploring how lives have changed for BiB families around the key priority research areas of social and emotional wellbeing, cardiometabolic health, and cognitive and sensorimotor development. Data are collected through multiple approaches, including community visits with families, and data collection with children in schools.
This protocol briefly describes the background of BiB, including existing data, and then the rationale and methods for the new data collection. It provides guidance for other researchers working with deprived and/or multi-ethnic populations to maximise recruitment and retention.
Born in Bradford – the beginning
BiB was established in Bradford in 2007 [1, 2]. It quickly developed into an applied population health research platform to address the high levels of child ill-health in the city. The city includes some of the most deprived areas in the UK, with high levels of infant mortality, childhood obesity, asthma and disability [3]. The aims were fourfold: 1) to investigate early life determinants of health and ill-health amongst families; 2) to use this evidence to develop, design and evaluate interventions to promote health; 3) to provide a model for integrating research into practice; and 4) to build and strengthen local research capacity in Bradford.
With modest initial funding, BiB had to turn to its local network of midwives, obstetricians, paediatricians and health visitors to recruit families and collect data. This model provided an efficient means of recruitment, and also served to promote ownership of the study amongst local health care providers which, in turn, helped to support our model of translating research into practice. As the children grew up this collaborative approach was extended into schools and local government.
A key decision during the design of the cohort study was to consent parents to linkage of routine health (primary and secondary care) and education records, and to allow the BiB research team to access these records. In collaboration with our local provider of electronic health records across primary care (The Phoenix Partnership, SystmOne) we were able to link 99% of BiB participants to their health record. We also worked with our local authority, Bradford Metropolitan District Council, to link BiB children to their Unique Pupil Identification Number (UPN), allowing us to match 84% with their education record.
The existing BiB resource
Between 2007 and 2010, the BiB cohort recruited 12,453 women with 13,776 pregnancies at 24–28 weeks gestational age, with 13,858 births (live births and stillbirths). In addition, 3449 of their partners were recruiteda.Footnote 1 A rich set of data were collected during pregnancy and in the immediate postnatal period [1, 2].
Follow-up since then has included growth and blood pressure measures by primary school nurses at age 5–6, [4, 5] whole cohort record-linkage to health and educational data, e.g. [6, 7], detailed bespoke data collection with sub-samples [8,9,10], and addition of biomarker data using stored biological samples, including genome-wide data, metabolomic data and Deoxyribonucleic acid (DNA) methylation [11, 12]. A summary of data collected can be seen in Fig. 1 and Additional File 1 and full details of recruitment and data collected can be found in the BiB cohort profile [1] and on the BiB website [13].
Analysis of BiB data has provided insights into the factors that affect health and wellbeing in pregnancy and early childhood, including on social and ethnic inequalities in health [14,15,16], the relationships between maternal gestational adiposity, gestational diabetes mellitus (GDM) and maternal circulating glucose concentrations and fetal growth, birth outcomes, infant and childhood health in South Asian and White European families [4, 5, 17,18,19], the associations of environmental stressors such as green space and air pollution on health e.g. [20,21,22], exposures that may influence development of asthma and allergies [23] and the role of genetic variation in human health [12]. BiB data have underpinned more than 100 journal publications; a full list can be found at https://borninbradford.nhs.uk/.
Strengths of the BiB cohort include:
The diversity of the cohort. Forty five per cent of families are of Pakistani origin, and half of Pakistani-origin mothers and fathers were born outside the UK [24]. Half of all BiB families are living within the fifth most deprived areas of England and Wales. This provides the opportunity to study the interplay of deprivation, ethnicity, migration and cultural characteristics, and their relationship to child health and wellbeing.
A life course approach. The assessment of multiple-‘omics data (including genome-wide data, some genomic sequenced data, epigenomic, and metabolomic data) and lifestyle in parents and children, with repeat measures of some of these in subgroups and with the current follow-up in the whole cohort supports life course epidemiology. That is, understanding how social, cultural, lifestyle and biological factors interact across the life course and across generations to influence development, health and wellbeing.
The whole systems, collaborative approach. BiB involves health and education professionals and a wide range of people in the local community in identifying research priorities and the most efficient and feasible ways of obtaining data to address these. We have integrated our research programme with key organisations within the city including the local authority, clinical commissioning groups, school networks, and voluntary sector organisations. Our goal is to work with these organisations to help set research priorities, influence commissioning of evidence-based services, improve the collection and accuracy of routinely collected data and to raise the bar in the monitoring of standards and the evaluation of interventions to improve health.
Participant and community engagement. We have established an active BiB parent governors group, which meets every two months, to help co-produce our research programme. We have a range of activities focused on communicating and disseminating findings to participants and the wider Bradford community, using traditional (birthday cards, newsletters) and social media (Facebook: https://www.facebook.com/BornInBradford, twitter: @bibresearch @bibparents) approaches. We hold regular events to talk with the community about our research, including family science festivals and pop-up events in local shopping centres. We are regularly featured in the press, including a yearly BBC Radio 4 radio programme that features BiB [25].
The city focus. The focus on a single city has facilitated engagement with participating families, including traditionally ‘seldom heard’ or ‘under-served’ groups such as families living in more deprived areas. It has also facilitated engagement with key stakeholders and the use of findings in local decision making. BiB has recruited a sample that is largely representative of city’s ethnic and deprivation profile [26].
Detailed data collection and routine data linkage. Detailed data collection during pregnancy, including oral glucose tolerance testing which is routinely offered to all pregnant women in Bradford, [18] and repeat ultrasound scans [19], infancy and childhood (the latter supplemented by health and educational record linkage), together with stored biological samples on most participants (Fig. 1), provide a unique opportunity for clinical and public health translational research on maternal and perinatal health and developmental origins of health and wellbeing.
BiB age 7–11 years follow-up: a resource for future research
Multi-method approach
Now that our BiB children are all of primary (elementary) school age, a full follow-up of the children and their families will provide insights into change in their family circumstances, health and wellbeing since birth.
We are employing a multi-method, three-armed approach to collect data from children and parents in community and school settings. This provides an efficient way of collecting data and maintains the close engagement with the whole community that was established at the study’s inception. In our community-based family assessments we conduct face to face visits with consenting parents, either on their own or with their children, in the family home or community venues. We have two independent school-based assessments: one working alongside school nurse teams to collect health-related data with children, and one working with teachers to collect cognitive and wellbeing assessments.
Priority research areas
The follow-up data collection focuses on three priority research areas (see below), with differences in ethnicity (including ancestry and migration to the UK) and socioeconomic position being cross-cutting themes. The links between the three focused areas are key to understanding how child and adult health and wellbeing develop.
Social and emotional wellbeing
Social and emotional wellbeing is key to the development of healthy behaviours, healthy relationships and educational attainment, prevention of behavioural problems and better mental health [27]. Early work from BiB suggests that consanguineous relationships, mainly seen as a risk factor for congenital anomalies, might simultaneously protect against psychosocial stress [28]. We have also found that Pakistani mothers report feeling more confident about their abilities as a parent and fewer of them adopt a hostile approach to parenting than White British women [29]. Using linked General Practice (GP) data, we have found that Pakistani mothers have a higher prevalence of undiagnosed and untreated depression and anxiety, and that these mothers have children with worse socio-emotional wellbeing at age 4–5 years [6, 14, 30].
The 7–11 years follow-up is supporting in-depth exploration of mechanisms underlying ethnic differences in social gradients in socio-emotional wellbeing, for example by taking into account the process of acculturation and experiences of discrimination (which are likely to differ between parents and children and by the length of time that parents have lived in the UK). This research will provide a strong evidence base for community and family interventions aimed at maximising child and adult well-being, particularly in deprived multi ethnic communities.
Growth, adiposity and cardiometabolic health
South Asian adults have a characteristic phenotype of proportionately greater adiposity, increased insulin resistance and higher rates of diabetes and cardiovascular disease compared with white British adults [31,32,33,34]. In BiB we have shown that despite being born smaller and lighter, infants of Pakistani-origin mothers have higher total fat mass, which seems in part to be explained by greater circulating fasting and post-load glucose in Pakistani women [17]. Using repeat ultrasound scan measurements we have shown that influences of GDM, fasting and postload glucose emerge prior to the pregnancy stage when gestational diabetes is usually diagnosed [19]. By age 4–5 years, the positive effect of maternal gestational hyperglycaemia seems to have attenuated, though greater maternal early pregnancy adiposity remains associated with greater offspring adiposity at this age [5]. We have also shown that Pakistani women are less likely to experience hypertensive disorders of pregnancy (HDP) compared to white British women, but that HDP is more robustly associated with offspring BP at age 4–5 years in Pakistani compared to white British children [4].
Given the very detailed measurements already available from pregnancy, infancy and early childhood (age 4–5 years), with the follow-up of the whole BiB cohort of children at 7–11 years, we will be able to explore the interplay of socioeconomic, intrauterine and postnatal exposures and molecular mediators on the development of cardio-metabolic traits in South Asian and White British children. We will also be able to explore the relationship of women’s pregnancy experience, and the experience of being parents, on adult cardiometabolic health.
Child cognitive and sensorimotor function
Evidence shows that childhood cognitive and visuomotor capabilities are associated with subsequent poorer health and educational outcomes [35,36,37,38]. Sensorimotor control is the emergent property that describes the interaction between sensory-perceptual (e.g. visual, haptic) and coordinative (e.g. motor planning) processes required to produce voluntary motor actions [35]. Here we focus on measuring children’s sensorimotor control whilst undertaking three fundamental movement tasks: tracking, aiming and steering. Cognitive abilities may integrate with sensorimotor processes to produce more complex goal directed actions and these abilities refer to higher-level mental processes involved in gaining knowledge, comprehending, remembering, decision-making and problem-solving [36]. We assessed three core components of cognition: Working Memory, Processing Speed and Inhibitory control as others were either likely to be confounded in our multi-ethnic sample (i.e. language) or were unfeasible to measure due to time-constraints (e.g. long-term memory). Evidence shows that abilities in both these domains of function are associated with subsequent poorer health and educational outcomes [37,38,39,40]. Children who are socially disadvantaged, including those living in poverty, are at a higher risk of cognitive and sensorimotor deficits [41, 42]. Studies have identified relationships between better social and emotional wellbeing and: manual dexterity among primary school aged children [43] and academic attainment [44] among 4–11 year olds. We have also found that White British children showed higher levels of performance than children from an Arabic education background when moving left-to-right, even on novel tasks, whereas the Arabic education children show the opposite asymmetry [45]. This may relate to exposure to writing and numerical systems that run right-to-left in early childhood before the child enters the UK education system and highlight the role of culture and family on differences in cognitive development.
Measuring child cognition and sensorimotor control at age 7–11 years allows us to relate early genetic, nutritional, environmental, behavioural and social factors to cognitive and sensorimotor capacity in the primary school years. This is essential for identifying those children who are at increased risk and require additional support in early life. As some cognitive and motor capabilities can be improved through specific training [46], this opens up the possibility of interventions that could have a profound impact on physical and mental health in adulthood.
