Early childhood sleep problems including less regular sleep routines, shorter nighttime sleep, and higher night awakening frequency constitute risk factors for probable attention deficit and hyperactivity disorder (ADHD) diagnosis at 10 years of age, according to study findings published in the Journal of Child Psychology and Psychiatry.
Investigators sought to evaluate the association between early childhood sleep and probable childhood ADHD diagnosis and if these prospective associations are mediated by childhood circulating inflammatory markers. They hypothesized shorter nighttime sleep duration would be the predominant sleep variable associated with ADHD in later childhood and the prospective association between sleep and ADHD would be mediated by interleukin-6 (IL-6) and C reactive protein (CRP).
They conducted an observational review of the Avon Longitudinal Study of Parents and Children (a UK birth cohort study) that included 7769 10-year-old children (49.6% girls; 98.3% White). Parent-reported regular sleep routines (yes, 93.2%), night awakening frequency (mean, 0.57 awakenings/night), and sleep duration (mean, 10.73 hours/night) had been collected at 3.5 years. Children with clinically relevant ADHD symptoms or probable ADHD diagnosis were identified with the Development and Wellbeing Assessment. Inflammatory markers IL-6 and CRP were obtained from blood samples collected at 9 years.
Investigators used logistic regression analyses to evaluate associations between 3.5-year sleep variables and ADHD at 10 years. The potential mediating role of inflammation in the associations between early sleep and ADHD were investigated with path analysis. Confounding family risk factors included early-age parenthood, financial difficulties, housing conditions, maternal education, parents’ substance abuse, and partner support.
They found less regular sleep routines (odds ratio [OR], 0.51; 95% CI, 0.28–0.93; P =.029), shorter nighttime sleep (OR, 0.70; 95% CI, 0.56–0.89; P =.004) and higher night awakening frequency (OR, 1.27; 95% CI, 1.06–1.52; P =.009) at 3.5 years were associated with higher odds of ADHD at 10 years. They noted IL-6 but not CRP at 9 years mediated the association between irregular sleep routines and ADHD (bias-corrected estimate, -0.002; P =.005), and between night awakening and ADHD (bias-corrected estimate, 0.002; P =.003). Their initial hypothesis that the association between irregular sleep routines and frequent night awakenings at 3.5 years with ADHD at 10 years was partially supported.
Significant study limitations include the observational nature of the study design, multiple unaccounted-for potential contributing factors (smoking, body mass index, viral infections, obstetric complications, cognition, depression), bias reporting sleep and probable ADHD, timepoints determined by data availability and not by potential relevancy, unaccounted for circadian variation in sleep markers’ secretion, selection bias, and the significantly lower prevalence of children with probable ADHD diagnosis than reported by previous studies.
“Shorter nighttime sleep duration, higher night awakening, and more irregular sleep routines at 3.5 years were associated with probable ADHD diagnosis at 10 years,” investigators concluded. They added that IL-6 but not CRP at 9 years mediated the associations between early sleep issues and likely ADHD diagnosis at 10 years. Investigators believe the relevant role of sleep problems in early childhood as a risk factor for ADHD is supported by these findings. They wrote “A nonresolving proinflammatory mechanism might be a contributory pathway explaining why sleep problems in early childhood are linked to subsequent ADHD, and thus provides further support to the role of inflammation in mechanistic pathways to ADHD.”
Morales-Muñoz I, Upthegrove R, Lawrence K, et al. The role of inflammation in the prospective associations between early childhood sleep problems and ADHD at 10 years: findings from a UK birth cohort study. J Child Psychol Psychiatry. Published online January 3, 2023. doi:10.1111/jcpp.13755
This article originally appeared on Psychiatry Advisor