Born in Bradford’s Better Start: an experimental birth cohort study to evaluate the impact of early life interventions

The aim of BiBBS is to evaluate the effects of multiple early life interventions on social and emotional development, communication and language development, and nutrition and obesity. This will be achieved by following families from pregnancy into childhood using linkage to routinely collected data. Our goal is to contribute robust evidence to policy makers, practitioners and local communities that will help inform health policy and planning, locally, nationally and internationally.

The cohort will also provide a strong foundation for future research into children’s health and development, including the roles of social and environmental factors, such as ethnicity, poverty and neighbourhood deprivation, and behavioural factors. It will include biobank resources to allow for the investigation of physiological, hormonal, genetic and epigenetic pathways.

This protocol outlines the study methods and design considerations for the initial phase of this experimental cohort study of mothers, their babies and their partners living in the BSB areas of inner city Bradford.

Bradford district, located in West Yorkshire in the North of England, is the 6^th largest district in England and is the 19^th most deprived local authority of 326 in England [17]. The Better Start Bradford area comprises three inner city areas of Bowling and Barkerend, Bradford Moor and Little Horton (see Fig. 1). The majority of the BSB area falls into the most deprived 10 % of areas in England [17]. The demographic characteristics of the BSB areas compared with Bradford and England are presented in Table 2. In summary, the three areas of BSB make up 12.3 % of the population of Bradford and are among the most deprived in the Bradford district and in England. BSB areas have a higher birth rate than Bradford district or England. The BSB areas are very ethnically diverse, with residents of Pakistani heritage forming the largest ethnic group (48.6 %) and a White British population of 24.8 %. An increasing number of families arriving from a range of central and eastern European countries, especially Poland, Slovakia and the Czech Republic, add to the diversity of the areas. Mortality and morbidity rates in these areas are higher than in Bradford district and England, and include a high infant mortality rate. There are higher rates of obesity and extremely poor oral health compared with Bradford district and England.

The BiBBS study aims to recruit 5000 babies over 5 years from January 2016 to December 2021. All women booked for delivery at BTHFT are offered an oral glucose tolerance test (GTT) at 26 to 28 weeks gestation. As 75 % of women attend for the GTT [14] the majority of women and their partners will be recruited in these clinics. For those who do not attend, recruitment will take place in community settings (e.g. at midwife appointments) and at other hospital appointments (e.g. diabetes clinics). Although every effort will be made to find and approach all eligible women, we predict reaching approximately 85 % of the eligible population through these methods. We assume, based on analysis of BiB data [14] and BTHFT data, that:

As such, we expect to recruit 4930 babies and 4440 mothers over a 5 year period.

The information sheets for pregnant women and for partners of pregnant women have been carefully developed for the population of BSB areas, with advice and feedback from members of the BSB community. They have a Flesch reading score of 64 (suitable for ages 12 upwards) and are appropriate for people with basic English as well as those under the age of 16 [19].

A large proportion (29 %) of the population in the BSB areas do not speak or read English. Information sheets, consent forms and baseline questionnaires will be translated/transliterated into the most common languages spoken by women requiring language support in the BSB areas: Urdu, Punjabi/Mirpuri, Slovakian, Polish, Sylheti. The translation process can be seen in detail in Additional file 1. Audio recorded spoken versions of the information sheet and consent forms will be produced for languages without a written form, or for those who are unable to read the language (Urdu, Mirpuri/Punjabi, Sylheti).

Interpreters will be used to facilitate inclusion of women who speak languages that are less common in the BSB area. Researchers will identify women’s language needs and will make use of the interpreters who attend the clinic / appointment with the woman to explain the study, take consent and translate a shortened version of the baseline questionnaire.

Informed consent will be obtained from expectant women (including consent for the baby/babies that the mother is expecting) and their partners.

Women and/or partners aged under 16 will be consented if deemed Gillick competent (having the intelligence and maturity to understand the research and the ability to understand the implications of that decision) [20]. Where the woman or partner is not able to consent themselves, their parent/guardian will be involved in the recruitment process and will be asked to provide consent for their child/ward’s participation. Consent will not be taken from any woman or partner aged 16 or over who is deemed not competent [21].

Following consent, the women will be invited to complete a baseline questionnaire and provide a blood sample, urine sample and have anthropometric measurements and carotenoid levels (a biomarker of antioxidant levels, indicating fruit and vegetable consumption) taken. Partners will complete the baseline questionnaire and provide an optional saliva sample and have anthropometric measurements taken.

A baseline questionnaire has been developed to provide information to support the evaluation of the BSB interventions. Key components include:

Where available and appropriate, validated questionnaires have been used. Additional sections have been developed based on the BiB cohort questionnaire [16] and through expert opinion of the authors and the local BSB community. The full questionnaire can be seen in Additional file 1. A shortened version of the questionnaire (Additional file 1) will be used where an interpreter is required. The partners questionnaire is a shortened version of the baseline questionnaire used for women and can be seen in Additional file 1.

The baseline questionnaire for women is designed to be partly self-completed and partly administered by a researcher using a tablet device. Researchers will sit with the women while they complete the self-completion questions and will be able to answer any queries. At the end of the questionnaire automated flags will indicate any safeguarding or mental health concerns and the researchers will be prompted to follow standard protocols.

The baseline Questionnaire for partners will be self-completed electronically or via a postal questionnaire.

As planned follow-up data will all be routinely collected, retention rates will depend on the availability and linkage with routine data. In the BiB study, 86 % of children in Bradford have been linked to schools and over 99 % of mothers and children have been linked with GP records, and the same success rate is expected in BiBBS [18].

To retain families and to keep them engaged, an annual newsletter and birthday card will be sent to each family. This was a successful element of the ongoing BiB cohort, and will be repeated for the new BiBBS cohort. The newsletter will gather the highlights from a BiBBS website over the year, focussing on celebrating key achievements, and findings from the research. Data linkage to GP records ensures that home addresses and the survival status of all participants are regularly updated on the database allowing newsletters and birthday cards to be sent to the most recent address and to be not sent where there has been a recent death.

Primary data captured by electronic forms will be synchronised with the cohort database to verify identifiers and validate newly captured data against existing data. Automatic interactive validation will be built into individual data item inputs in electronic forms and questionnaires, such as logical traps, format validations, range limiters and, automated questionnaire flow with mandatory values. Electronic data capture clients for primary data and biosample tracking data will synchronise with the cohort database, from which unattended transform and report functions will provide regular datasets for researchers to analyse to ensure data quality standards are being met. Record matches for routine data linkage will be validated on the basis of unique identifiers (e.g. NHS number) plus multiple non-unique identifiers (e.g. surname, date of birth) where possible. Where unique identifiers are not available, iterative deterministic matching on the basis of multiple sets of non-unique identifiers will be used. The central database, hosted by BTHFT, will store data obtained from all sources listed under Data Collection. Data from each source will be linked at the BiBBS person level and will be structured and maintained by BiBBS data managers as a long term strategic store to service cohort data capture, analysis and other research activities as necessary. The entire database schema and data will be backed up nightly. Further details of the data management process can be seen in Additional file 1.

The BiBBS experimental cohort design will enable evaluation of the BSB interventions using both experimental and quasi-experimental methods, in addition to traditional epidemiological approaches to the analysis of observational cohort data.

The success of BiBBS is dependent upon input from a wide range of people, organisations and academic partners. The cohort will be managed and monitored using the same management structure established for the BiB cohort [16] and the groups established for BSB (e.g. Partnership board and the CRAG). Full details of the management structure can be seen in Additional file 1.

The BiBBS experimental cohort study will enable the evaluation of the BSB interventions and increase understanding about how to improve health and development in inner city Bradford. It will contribute knowledge and understanding about the effects of prenatal and child interventions, and the causes of disease that will have international relevance. The BiBBS cohort also offers a platform to develop and test new early childhood interventions, and conduct research projects in a diverse population. Researchers with relevant proposals are encouraged to visit the BiB website (www.​borninbradford.​nhs.​uk) to find out more about the application and selection process.

In addition, data and samples collected throughout the course of the cohort will be available to external researchers and proposals for collaboration will be welcomed. Until recruitment is complete, and all routine outcome measures have been linked and data cleaned, such access may be limited. Researchers with proposals to use the cohort data should complete an outline data request pro forma available on the BiB website (www.​borninbradford.​nhs.​uk).