Young Motherhood, Child ADHD Link Explained

Brennan H. Baker

There are several factors, mostly involving socioeconomic disadvantages, increase the risk of young mothers giving birth to children with attention deficit/hyperactivity disorder (ADHD).

A team, led by Brennan H. Baker, Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, examined the associations of maternal age with ADHD clinical range diagnoses based on the Child Behavior Checklist and NIH Toolbox Flanker Attention Scores using mixed logistic and linear regression models, respectively.

Why?

It is currently unclear why young motherhood is commonly associated with ADHD.

In the cross-sectional ABCD study, the investigators identified 11,878 pediatric patients from 22 sites across the US between June 1, 2016 and October 15, 2018, 8514 of which were included in the final analysis. The final patient population was aged 8-11 years. There were 2260 twins or triplets, 265 adopted children, and 839 younger siblings excluded from the final analysis.

The investigators conducted confounding and causal mediation analyses using genotype array, demographic, socioeconomic, and prenatal environment data to investigate which genetic and environmental variables could explain the association between young maternal age and child ADHD.

Model Results

The crude model results show for each 10-year increase in maternal age there was a 32% decrease in the odds of ADHD clinical range diagnosis (OR, 0.68; 95% CI, 0.59-0.78), as well as a 1.09-point increase in the NIH Flanker Attention Scores (β = 1.09; 95% CI, 0.76, 1.41). This indicates a better child visual selective attention.

After adjusting for confounders, they investigators found the associations were weakened.

The strongest confounders were family income, caregiver education, and ADHD polygenic risk scores for ADHD clinical range diagnoses. For NIH Flanker Attention Scores, the strongest confounders were family income, caregiver education, and race/ethnicity. Breastfeeding duration, prenatal alcohol exposure, and prenatal tobacco exposure were the source of up to 18%, 6%, and 4% mediation, respectively.

“Socioeconomic disadvantages were likely the primary explanation for the association of young maternal age with child ADHD, although genetics and modifiable environmental factors also played a role,” the authors wrote. “Public policies aimed at reducing the burden of ADHD associated with young motherhood should target socioeconomic inequalities and support young pregnant women by advocating for reduced prenatal tobacco exposure and healthy breastfeeding practices after childbirth.”

Recently, investigators found that preterm birth and family history result in an increased risk of developing a psychiatric disorder by age 15, with many also suffering from 2 or 3 disorders, mainly anxiety, ADHD, and major depression.

A team, led by Jean A. Frazier, MD, Eunice Kennedy Shriver Center at the University of Massachusetts Medical School, evaluated the prevalence, co-occurrence, sex differences, and functional correlates of Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) psychiatric disorders in 15-year-old adolescents born extremely preterm.

Using the parent questionnaires, the investigators learned a positive family history of psychiatric disorders more frequently occurred in adolescents with at least 3 psychiatric disorders.

The study, “Maternal age at birth and child attention-deficit hyperactivity disorder: causal association or familial confounding?,” was published online in the Journal of Child Psychology and Psychiatry.