Fig. 3.

The figures show the prevalence of lactose intolerance (a), celiac disease (b), diarrhea (c), constipation (d), daytime enuresis (e) and encopresis (f) in our study groups and the statistical comparison to the comparison group consisting of twins who screened negative for neurodevelopmental disorders. Statistical significance is marked by stars, where p < 0.05 is represented by *, p < 0.01 by ** and p < 0.001 by ***. NDDs neurodevelopmental disorders, ASD autism spectrum disorder, ADHD attention-deficit/hyperactivity disorder and LD learning disorder