BackgroundA high prevalence of autism spectrum disorder is reported in children born extremely preterm (EP), but an even larger proportion of survivors are affected by subclinical difficulties than meet diagnostic criteria. The aims of this study were to investigate autistic traits associated with the broader autism phenotype in a cohort of young adults born EP, and explore how these traits relate to emotion recognition, empathy and autism symptom presentation in childhood. The prevalence of autism diagnoses was also investigated.MethodsOne hundred and twenty-nine young adults born before 26 weeks of gestation and 65 term-born controls participated in the 19-year follow-up phase of the EPICure studies. In addition to a clinical interview, participants completed the Broader Autism Phenotype Questionnaire (BAPQ), the Empathy Quotient questionnaire, and the Frankfurt Test and Training of Facial Affect Recognition. The Social Communication Questionnaire (SCQ) was completed by the participants’ parents at age 11 years.ResultsEP born young adults scored significantly higher on the BAPQ in comparison with their term-born peers, indicating greater autistic traits. Among EP participants, BAPQ scores were correlated with SCQ scores in childhood (r = 0.484, p < 0.001). EP young adults had significantly lower scores in emotion recognition and empathy in comparison with controls; however, this effect was mediated by IQ. At 19 years, a diagnosis of autism was reported by 10% of EP participants versus 1.6% of controls, whereas 31% of EP participants scored above the cut-off for the broader autism phenotype in comparison with 8.5% of term-born controls.LimitationsThe high attrition of EP participants from lower socio-economic backgrounds and with lower cognitive functioning may have led to an underrepresentation of those presenting with difficulties associated with autism.ConclusionsA larger proportion of EP survivors are affected by difficulties associated with autism than have confirmed diagnoses, with a moderate correlation between autism symptom scores in childhood and autistic traits in young adulthood. EP young adults had significantly higher autism symptom scores and a larger proportion had a diagnosis of autism than controls. Screening for autistic traits at set points throughout childhood will help identify those EP individuals at risk of social difficulties who may benefit from intervention.