Obesity before pregnancy may amplify offspring ADHD risk

Maternal obesity appears to contribute to offspring inattentiveness or hyperactivity problems and may precede an attention deficit/hyperactivity disorder (ADHD) diagnosis, a recent study has shown.

The study included 1,605 mothers, whose maternal body mass index (BMI) was calculated using reported height and weight. Paternal information was obtained from maternal reports. Participants were followed 7–8 years after to determine whether their children had been diagnosed with ADHD or anxiety.

Nearly a quarter of mothers had prepregnancy obesity, with BMI ≥30 kg/m². This correlated with almost double the risk of the child having maternally reported clinically diagnosed ADHD (adjusted risk ratio [aRR], 1.96, 95 percent confidence interval [CI], 1.29–2.98). Risk estimates were computed using multivariable, modified Poisson regression, using mothers with BMI <25 kg/m² as a reference.

The corresponding offspring ADHD risk was likewise elevated in those with class II+ obesity, defined as BMI ≥35 kg/m², (aRR, 1.82, 95 percent CI, 1.21–2.74).

These associations persisted when ADHD was assessed using the Vanderbilt ADHD Diagnostic Parent Rating Scale. Maternal obesity classes I (aRR, 1.77, 95 percent CI, 1.18–2.66) and II+ (aRR, 1.78, 95 percent CI, 1.21–2.62) were both significant risk factors for ADHD at 8 years of age.

The same was true when assessed through the Strengths and Difficulties Questionnaire, which confirmed that maternal obesity class I (aRR, 1.84, 95 percent CI, 1.24–2.73) and class II (aRR, 1.79, 95 percent CI, 1.21–2.65) almost doubled the risk of borderline hyperactivity/inattention at age 7 years.