Original Research The association between body mass index, primary healthcare use and morbidity in early childhood: findings from the Born In Bradford cohort study B. Kelly a,* , J. West a , T.C. Yang a , D. Mason a , T. Hasan a,b , J. Wright a a Bradford Institute for Health Research, Bradford Teaching Hospitals NHS Foundation Trust, Bradford, UK b Department of Health Sciences, University of York, York, UK article info Article history: Received 8 August 2018 Received in revised form 1 October 2018 Accepted 25 October 2018 Keywords: Childhood BMI Primary care use Childhood morbidity Routine data abstract Objectives: The objective of the article was to examine the association between body mass index (BMI), health and general practice (GP) healthcare use in early childhood. Study design: This study is a prospective cohort study. Methods: Multivariate Poisson and logistic regression models were used to explore the as- sociation between BMI and health outcomes using data from the Born In Bradford cohort study, linked to routine data capturing objective measures of BMI at age 5 years, alongside GP appointment rates, GP prescriptions and specific morbidities in the subsequent 3-year period. Results: Compared with healthy weight, children who were obese at the age of 5 years had significantly higher rates of GP appointments (incident rate ratio 1.14, 95% confidence in- terval [CI]: 1.06e1.23), GP prescriptions (incident rate ratio 1.15, 95% CI: 1.04e1.27), asthma (odds ratio 1.46, 95% CI: 1.21e1.77), sleep apnoea (odds ratio 2.50, 95% CI: 1.36e4.58), in- fections (incident rate ratio 1.19, 95% CI: 1.08e1.30), antibiotic prescriptions (incident rate ratio 1.25, 95% CI: 1.10e1.42) and accidents (incident rate ratio 1.20, 95% CI: 1.01e1.42) in the subsequent 3 years. Underweight children were found to have higher rates of GP ap- pointments (incident rate ratio 1.25, 95% CI: 1.04e1.52), but there were no differences be- tween overweight and healthy weight children. Conclusions: Childhood obesity was found to be associated with increased primary healthcare use and a range of poorer health outcomes at the age of 8 years, underlining the importance of reducing childhood obesity in early childhood. © 2018 The Royal Society for Public Health. Published by Elsevier Ltd. All rights reserved. * Corresponding author. Bradford Institute for Health Research, Bradford Royal Infirmary, Duckworth Lane, Bradford BD9 6RJ, UK. Tel.: þ44 01274 364474. E-mail address: brian.kelly@bthft.nhs.uk (B. Kelly). Available online at www.sciencedirect.com Public Health journal homepage: www.elsevier.com/puhe public health 167 (2019) 21 e27 https://doi.org/10.1016/j.puhe.2018.10.019 0033-3506/© 2018 The Royal Society for Public Health. Published by Elsevier Ltd. All rights reserved.