ADHD symptoms and diagnosis in adult preterms: systematic review, IPD meta-analysis, and register-linkage study

Abstract

Background 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.

Multidisciplinary and neuroimaging findings in preterm born very low birthweight individuals from birth to 28 years of age: A systematic review of a Norwegian prospective cohort study

“…Increased psychiatric morbidity from 14 years to 19 and 26 years is in line with two comprehensive meta‐analyses in the APIC consortium, showing long‐term consequences of being born preterm with VLBW into adulthood, especially internalising problems, 5 anxiety and mood disorders, attention deficit hyperactivity and autism spectrum disorders 6 . The increased risk of attention deficit hyperactivity disorder is also supported by a recent publication that includes register data from Finland 74 . A large multinational cohort study using data from several Nordic registers has documented an increased risk of autism spectrum disorder for each week of decreasing gestation from week 40 to week 24 75 …”

“…6 The increased risk of attention deficit hyperactivity disorder is also supported by a recent publication that includes register data from Finland. 74 A large multinational cohort study using data from several Nordic registers has documented an increased risk of autism spectrum disorder for each week of decreasing gestation from week 40 to week 24. 75 Our finding of reduced expiratory airflow of the lungs is confirmed by a meta-analysis of individual participant data in the APIC consortium, where the mean difference was −0.78SD between the very preterm/VLBW (n = 935) and control participants (n = 722).…”

Mental health in adults born preterm with very low birth weight at 14 and 26 years of age assessed by the Strengths and Difficulties Questionnaire

“…Nevertheless, both individual participant data meta-analyses and a registry-linkage study have reported a higher prevalence of ADHD. 5,6 The lack of significant differences between the VLBW and control group regarding peer relationship problems and prosocial behaviour contradicts previously published results. Poor social functioning of adults born preterm has been reported in terms of deficits in romantic partnership and self-reported poorer relationship with friends.…”

“…However, it should be noted, as pointed out as a limitation, that the SDQ combines hyperactivity and inattention and includes this in the externalising problems scale, while attention problems are not part of the ASEBA ASR externalising scale. Nevertheless, both individual participant data meta‐analyses and a registry‐linkage study have reported a higher prevalence of ADHD 5,6 …”

“…Long‐term follow‐up of individuals born with VLBW to adulthood has uncovered a high prevalence of internalising problems, 4 for example emotional difficulties, such as relational issues, anxiety, and depressive symptoms and disorders 5 . Findings of externalising problems, like conduct and hyperactivity traits, are mixed; Pyhala et al 4 reported less externalising problems, including less rule‐breaking behaviour, while others have found more attention deficit hyperactivity disorder (ADHD) 5,6 . Anderson et al 5 also reported higher odds of meeting criteria for autism spectrum disorder in adulthood.…”