This study examined differences in ADHD symptoms and diagnosis between preterm and term-born adults (≥18 years), and tested if ADHD is related to gestational age, birth weight, multiple births, or neonatal complications in preterm borns.
Methods
(1) A systematic review compared ADHD symptom self-reports and diagnosis between preterm and term-born adults published in PubMed, Web of Science, and PROQUEST until April 2021; (2) a one-stage Individual Participant Data(IPD) meta-analysis (n = 1385 preterm, n = 1633 term; born 1978–1995) examined differences in self-reported ADHD symptoms[age 18–36 years]; and (3) a population-based register-linkage study of all live births in Finland (01/01/1987–31/12/1998; n = 37538 preterm, n = 691,616 term) examined ADHD diagnosis risk in adulthood (≥18 years) until 31/12/2016.
Results
Systematic review results were conflicting. In the IPD meta-analysis, ADHD symptoms levels were similar across groups (mean z-score difference 0.00;95% confidence interval [95% CI] −0.07, 0.07). Whereas in the register-linkage study, adults born preterm had a higher relative risk (RR) for ADHD diagnosis compared to term controls (RR = 1.26, 95% CI 1.12, 1.41, p < 0.001). Among preterms, as gestation length (RR = 0.93, 95% CI 0.89, 0.97, p < 0.001) and SD birth weight z-score (RR = 0.88, 95% CI 0.80, 0.97, p < 0.001) increased, ADHD risk decreased.
Conclusions
While preterm adults may not report higher levels of ADHD symptoms, their risk of ADHD diagnosis in adulthood is higher.
Impact
- Preterm-born adults do not self-report higher levels of ADHD symptoms, yet are more likely to receive an ADHD diagnosis in adulthood compared to term-borns.
- Previous evidence has consisted of limited sample sizes of adults and used different methods with inconsistent findings. This study assessed adult self-reported symptoms across 8 harmonized cohorts and contrasted the findings with diagnosed ADHD in a population-based register-linkage study.
- Preterm-born adults may not self-report increased ADHD symptoms. However, they have a higher risk of ADHD diagnosis, warranting preventive strategies and interventions to reduce the presentation of more severe ADHD symptomatology in adulthood.
Robinson, R., Girchenko, P., Pulakka, A., Heinonen, K., Lähdepuro, A., Lahti-Pulkkinen, M., Hovi, P., Tikanmäki, M., Bartmann, P., Lano, A., Doyle, L. W., Anderson, P. J., Cheong, J. L. Y., Darlow, B. A., Woodward, L. J., Horwood, L. J., Indredavik, M. S., Evensen, K. A. I., Marlow, N., Johnson, S., de Mendonca, M. G., Kajantie, E., Wolke, D., & Räikkönen, K. (2022). ADHD symptoms and diagnosis in adult preterms: systematic review, IPD meta-analysis, and register-linkage study. Pediatric Research. https://doi.org/10.1038/s41390-021-01929-1