Mortality, morbidity and educational outcomes in children of consanguineous parents in the Born in Bradford cohort

Background Children of consanguineous parents have a higher risk of infant and childhood mortality, morbidity and intellectual and developmental disability. Methods Using a prospective UK based longitudinal family cohort study we quantify differences according to the consanguinity status of children from birth to age 10 in mortality, health care usage, two health and three educational outcomes. Results Compared to children whose parents were not related children whose parents were first cousins were more likely to die by the age of 10 years (odds ratio 2.81, 95% CI 1.82-4.35) to have higher rates of primary care appointments (incident rate ratio 1.39, 95% CI 1.34-1.45) and more prescriptions (incident rate ratio 1.61, 95% CI 1.50-1.73). Rates of hospital accident and emergency attendance (incident rate ratio 1.21,95% CI 1.12-1.30) and hospital outpatients’ appointments (incident rate ratio 2.21,95% CI 1.90-2.56) are higher. Children whose parents are first cousins have higher rates of speech/ language development difficulties (odds ratio 1.63, 95% CI 1.36-1.96) and learning difficulties (odds ratio 1.89, 95% CI 1.28-2.81). When they begin school children whose parents are first cousins are less likely to reach phonics standards (odds ratio 0.73, 95% CI 0.63-0.84) and less likely to show a good level of development (odds ratio 0.61, 95% CI 0.54-0.68). At age 10 there are higher numbers with special educational needs who are from first cousin unions when compared to all children whose parents are not blood relations (odds ratio 1.38, 95% CI 1.20-1.58). Effect sizes for consanguinity status are similar in univariable and multivariable models where a range of control variables including deprivation are added. Conclusions There is higher childhood mortality and greater use of health care as well as higher rates of learning difficulties, speech and language development challenges and substantive differences in education outcomes in children whose parents are first cousins