Asthma, eczema and hay fever and are common diseases in childhood and responsible for a significant burden on families and health services. Atopic eczema, hay fever (allergic rhinitis) and atopic asthma often co-exist. Early diagnosis and appropriate management can reduce progression and severity of these diseases.
The Born in Bradford (BiB) birth cohort includes over 13,500 children born between 2007 and 2011, with around half born to women of Pakistani ethnicity. Linked primary care and hospital admission data are available for 97% of BiB children. Two sub-studies within BiB, the Allergy and Infection Study (ALL IN, n=2559) and Mechanisms of the Development of ALLergy (MeDALL, n=1814), have collected detailed parental questionnaire data at age 1 and 2 years (ALL IN) and at 4 years (MeDALL). The current data collection phase for the whole BiB cohort, Growing Up, at ages 7-11 years is ongoing and also includes questions on these outcomes.
The BiB data provide an opportunity to investigate trajectories of allergic disease and asthma through childhood, by ethnic group. The linked primary care and hospital electronic health records (EHR) will contribute a wealth of data which can be analysed with machine learning methods. There is uncertainty over the validity of routine data but the extensive BiB questionnaire data at different ages provide a rare opportunity to test this.
The aims of this proposed study are:
1) to link research and routine data to explore early life and childhood longitudinal trajectories and describe clinical phenotypes of asthma, eczema and hay fever;
2) to investigate ethnic inequalities in access to care and presentation of these diseases
3) to investigate early life risk factors for these diseases
Questionnaire data are available from the BiB ALL IN sub-study at age 1 year, including questions on pets, family history of asthma/eczema/hay fever, housing conditions (damp, heating, flooring, bedding etc.), and at 2 years (as for age 1 plus eczema, hay fever, food allergy). Detailed data relevant to asthma, eczema and hay fever are available for the MeDALL sub-study participants at 4 years, including skin prick testing for 2269.
BiB receive regular extracts of primary care EHR data on diagnoses and prescriptions for BiB children, which will be linked to the BiB maternal baseline questionnaire data, including socio-demographic and household characteristics. Linked hospital admissions data are available from the Bradford Royal Infirmary. We will also compare EHR data and questionnaire data from the Avon Longitudinal Study of Parents and Children (ALSPAC).
Latent class analysis or other cluster methods, such as k-means clustering, will be used to identify clinical phenotypes of asthma, eczema and hay fever. Longitudinal extensions of these cluster methods will be used to describe trajectories over age.
This study will provide important data on the validity of routine primary care EHR for asthma and allergic diseases, which is relevant as EHR are increasingly used for research studies. The comparison of questionnaire and EHR data will indicate whether there are ethnic differences in access to primary care for these diseases. Identification of clinical phenotypes of asthma, eczema and hay fever will inform appropriate treatment and management and the identification of factors associated with disease progression or severity could indicate potential prevention strategies.