Serum Occludin and Zonulin Levels in Children With Attention-Deficit/Hyperactivity Disorder and Healthy Controls

Objective: To evaluate zonulin and occludin levels, potentially associated with immunological pathways in the gut-brain axis, in children with attention-deficit/hyperactivity disorder (ADHD). Method: We examined the association between serum levels of zonulin and occluding, and behavioral/emotional problems in children with ADHD. 40 medicationnaïve children meeting Diagnostic and statistical (DSM-5) criteria for ADHD (11 females; mean (SD) age 9.4 (1.6) years) and 39 healthy comparisons (12 females; mean (SD) age 9.3 (1.9) years) were studied. Serum zonulin and occludin levels were measured by (ELISA). Result: We found higher mean (SD) serum zonulin levels [37.1 (28.2) vs 8.1 (4.5) ng/mL; P<0.001) and occludin levels [2.4 (1.6) vs 0.6 (0.4) ng/mL; P<0.001] in the ADHD group compared to control group. Serum zonulin levels had a positive correlation with weight (r=0.452; P=0.003) and BMI (r=0.401; P=0.01) among children with ADHD. Serum zonulin and occludin levels also had a positive correlation with Conners parent rating scale scores (r=0.58; P<0.001), and Strengths and difficulties questionnaire scores (r=0.49; P<0.001). Multiple linear regression analysis revealed that age, sex, weight, conduct problems and oppositional sub-scores were significant predictors of increased serum zonulin levels. Conclusion: These data confirm an association between ADHD, and serum zonulin and occludin levels. Pathophysiological and clinical significance of these findings needs to be elucidated.