Childhood Physical Health and Attention Deficit/Hyperactivity Disorder: A Systematic Review and Meta-Analysis of Modifiable Factors

Abstract

Although neurobiologic and genetic factors figure prominently in the development of attention deficit/hyperactivity disorder (ADHD), adverse physical health experiences and conditions encountered during childhood may also play a role. Poor health is known to impact the developing brain with potential lifelong implications for behavioral issues. In attempt to better understand the relationship between childhood physical health and the onset and presence of ADHD symptoms, we summarized international peer-reviewed articles documenting relationships between a select group of childhood diseases or health events (e.g., illnesses, injuries, syndromes) and subsequent ADHD outcomes among children ages 0–17 years. Drawing on a larger two-phase systematic review, 57 longitudinal or retrospective observational studies (1978–2021) of childhood allergies, asthma, eczema, head injury, infection, or sleep problems and later ADHD diagnosis or symptomatology were identified and subjected to meta-analysis. Significant associations were documented between childhood head injuries, infections, and sleep problems with both dichotomous and continuous measures of ADHD, and between allergies with dichotomous measures of ADHD. We did not observe significant associations between asthma or eczema with ADHD outcomes. Heterogeneity detected for multiple associations, primarily among continuously measured outcomes, underscores the potential value of future subgroup analyses and individual studies. Collectively, these findings shed light on the importance of physical health in understanding childhood ADHD. Possible etiologic links between physical health factors and ADHD are discussed, as are implications for prevention efforts by providers, systems, and communities.

Appendix 1

Search terms used for meta-analytic review of childhood physical health risk factors for attention deficit/hyperactivity disorder (ADHD).

Component	Search terms
Attention deficit/hyperactivity disorder (ADHD) related terms	(((“attention deficit”) OR (“hyperactivity disorder*”) OR (“deficit hyperactiv*”) OR (“ADHD”) OR (“deficit disorder*”) OR (“minimal brain dysfunction”) OR (“minimal brain damage”) OR (“MBD”) OR (“brain injured child syndrome*”) OR (“hyperactive child syndrome*”) OR (“hyperactive syndrome*”) OR (“impulse disorder*”) OR (“hyperkinetic disease”) OR (“hyperkinetic syndrome*”) OR (“hyperkinetic reaction of childhood”)) OR ((“ADD” AND (disorder OR attention OR hyperactiv*))) OR ((“attention problem*”) OR (“inattenti*”) OR (“hyperactiv*”) OR (“hyperkines*”)))
Child health terms	AND (((“nutrition*”) OR (“deficienc*”) OR (“iron”) OR (“ferritin”) OR (“transferrin”) OR (“anemia”) OR (“copper”) OR (“zinc”) OR (“magnesium”) OR (“polyunsaturated fatty acids”) OR (“fatty acid*”) OR (“folate”) OR (“nutritional surplus*”) OR (“fat”) OR (“sugar*”) OR (“sodium”) OR (“food additive*”) OR (“food color additive*”) OR (“food color*”) OR (“FD&C Yellow”) OR (“FD&C Red”) OR (“preservatives”) OR (“sodium benzoate”) OR (“diet”) OR (“IgG”) OR (“western diet”) OR (“malnutrition”) OR (“electronic*”) OR (“television”) OR (“TV”) OR (“video game*”) OR (“screen time”) OR (“sleep”) OR (“built environment”) OR (“nature”) OR (“green space”) OR (“physical activity”) OR (“exercise”) OR (“injury”) OR (“infection*”) OR (“bacteria*”) OR (“viral”) OR (“virus”) OR (“fungus”) OR (“fungal”) OR (“protozoa*”)))