Maternal serum C-reactive protein (CRP) and offspring attention deficit hyperactivity disorder (ADHD)

Area of Science:

• Neuroscience
• Epidemiology
• Immunology

Background:

• Fetal exposure to infection and inflammation is linked to offspring neuropsychiatric disorders.
• Previous research on maternal inflammation and ADHD risk has yielded mixed results.
• C-reactive protein (CRP) is a key biomarker for inflammation.

Purpose of the Study:

• To investigate the association between early gestational maternal C-reactive protein (CRP) levels and the risk of attention-deficit/hyperactivity disorder (ADHD) in offspring.
• To explore if maternal inflammation during early pregnancy influences ADHD development.

Main Methods:

• Nested case-control study using data from the Finnish Prenatal studies of ADHD (FIPS-ADHD).
• Included 1079 singleton children diagnosed with ADHD and an equal number of matched controls born between 1998-1999.
• Maternal CRP levels were measured from serum collected in the first or early second trimester using latex immunoassay.

Main Results:

• Elevated maternal CRP levels, analyzed continuously, showed no significant association with offspring ADHD risk (OR 1.05, 95% CI 0.96-1.15).
• No significant association was found when CRP was analyzed in the highest quintile (OR 1.18, 95% CI 0.88-1.58).
• Results remained consistent across sexes and ADHD cases with or without comorbid autism spectrum disorder (ASD) or conduct disorder.

Conclusions:

• This study found no significant association between early gestational maternal CRP levels and offspring ADHD risk.
• The findings suggest that maternal immune activation may impact different neuropsychiatric disorders through distinct biological pathways.
• Unlike associations observed in ASD and schizophrenia, maternal inflammation in early pregnancy does not appear to be a risk factor for ADHD.