PT - JOURNAL ARTICLE AU - Stephen Turner AU - Lorna Aucott TI - Reduced antenatal and birth size and time to onset of asthma AID - 10.1183/13993003.congress-2020.4986 DP - 2020 Sep 07 TA - European Respiratory Journal PG - 4986 VI - 56 IP - suppl 64 4099 - http://erj.ersjournals.com/content/56/suppl_64/4986.short 4100 - http://erj.ersjournals.com/content/56/suppl_64/4986.full SO - Eur Respir J2020 Sep 07; 56 AB - Background: There is an inconsistent association between small for gestational age (SGA) at birth and increased risk for later asthma diagnosis. As individuals become older the relationship between size in early life and asthma may become weaker. Our hypothesis was that reduced size during fetal life is more clearly related to time to first asthma episode than asthma per se.Methods: Routinely acquired fetal, neonatal and maternal data collected between 1987 and 2015 were linked to hospital admission and primary care prescribing data. Outcomes were any asthma inhaler prescribing, any hospital admission for asthma, time to first prescription and time to first admission.Results: Data were linked in 63930 individuals, mean age was 18.6years. The proportion prescribed any asthma inhaler was 18% (n=11798) and 4% had at least one asthma admission (n=2740). Measurements in the first, second and third trimesters and at birth were available in 34685, 36136, 22854 and 63280 individuals respectively. There were few associations (and which were of small magnitude) between SGA and asthma per se, e.g. first trimester size was 0.5mm smaller for those with any asthma prescription. Reduced length in the first trimester and at birth were associated with shorter time to first asthma admission (Hazard ratio (HR) 0.92 per z score [95%CI 0.88,0.97] and 0.96 [0.92,1.00]). Reduced weight in the third trimester and birth were associated with a shorter time to first inhaled steroid prescription (HR 0.91 per z score [95%CI 0.86,0.96] and 0.96 [0.99,0.99]).Conclusions: These findings support the hypothesis that SGA is a stronger predictor of early onset asthma rather than asthma per se.FootnotesCite this article as: European Respiratory Journal 2020; 56: Suppl. 64, 4986.This abstract was presented at the 2020 ERS International Congress, in session “Respiratory viruses in the "pre COVID-19" era”.This is an ERS International Congress abstract. No full-text version is available. Further material to accompany this abstract may be available at www.ers-education.org (ERS member access only).