Ivan Belica

Dr. Ivan Belica


Research Focus & Metrics

Academic Career Length

7Years (2020-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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Katarína BabinskaKatarína Babinska
Katarína Babinska
HCHana Celusakova
Hana Celusakova
IBIvan Belica
Ivan Belica
ZSZofia Szapuova
Zofia Szapuova
IWIveta Waczulíková
Iveta Waczulíková
DODaniela Ostatnikova
Daniela Ostatnikova
Autism spectrum disorders (ASD) are characterized by impairments in social interaction, communication, and restricted, stereotyped behavior. Gastrointestinal (GI), nutritional, and feeding problems are often reported in ASD. We investigated the prevalence of GI symptoms, food selectivity, and mealtime difficulties, and their associations with dietary interventions, food supplement use, and behavioral characteristics in a sample involving 247 participants with ASD and 267 controls aged 2–18 years. Data were collected by a questionnaire. GI symptoms were observed in 88.9% of children and adolescents with ASD, more often in girls than in boys. High rates of food selectivity (69.1%) and mealtime problems (64.3%) were found. Food supplements were used by 66.7% of individuals, mainly vitamins/minerals, probiotics, and omega-3 fatty acids. In the ASD sample, 21.2% of subjects followed a diet, mostly based on gluten and milk restriction, including individuals exhibiting food selectivity. Frequency of GI symptoms, food selectivity, and mealtime problems correlated weakly, but significantly with behavioral characteristics in the ASD group, but not with food supplement use. The study demonstrated that higher frequency of GI symptoms, food selectivity, and mealtime problems are a common problem in pre-schoolers, schoolchildren, and adolescents with ASD, and together with dietary modification, they are significantly associated with ASD.

KBKristina Bartakovicova
Kristina Bartakovicova
PKPetra Kemenyova
Petra Kemenyova
IBIvan Belica
Ivan Belica
ZSZofia Janik Szapuova
Zofia Janik Szapuova
Katarína StebelováKatarína Stebelová
Katarína Stebelová
Katarína BabinskaKatarína Babinska
Katarína Babinska
In children with autism spectrum disorder (ASD), sleep disturbances are a frequent comorbidity with an adverse effect on their behavior and functioning. It was suggested that melatonin deficit is at least partly responsible for the sleep problems. The study aimed to investigate, in a sample of 56 children with ASD aged 2.8–13.3 years, if the sleep problems and melatonin secretion can serve as predictors of adaptive functioning and severity of the ASD core symptoms. We demonstrated that, after adjustment for age, the Sleep score assessed by the Children’s Sleep Habits Questionnaire predicts the Adaptive behavior composite score only in children younger than 6 years, and the preferred predictive model is for the domain Socialization. The age-adjusted Sleep score predicted Externalizing and Internalizing maladaptive behavior, with a near-zero contribution of age to the relationship between the Internalizing maladaptive behavior and Sleep score. After adjustment for age, the reduced night-time melatonin secretion predicted a higher severity of ASD symptoms in the domain Social affect and the Calibrated Severity Score, but not the sleep problems. Our results emphasize the importance of assessing sleep problems as a modifiable predictor of behavior in children with ASD and support the hypothesis about the role of melatonin in pathophysiology of ASD.

13 April 2022 in Toxics
Verified
Journal Article
Open access
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ZSZofia Szapuova
Zofia Szapuova
Lubica ArgalasovaLubica Argalasova
Lubica Argalasova
DVDiana Vondrova
Diana Vondrova
KJKatarina Jansakova
Katarina Jansakova
IBIvan Belica
Ivan Belica
DODaniela Ostatnikova
Daniela Ostatnikova
The study focuses on current issues of adaptive behavior in individuals with autism spectrum disorder (ASD) and on the possible risk factor of environmental tobacco smoke (ETS). Children examined at the Academic Research Center for Autism (ARCA) in Bratislava were involved in the study. The study sample included 84 children (71 boys) with ASD (average age 5.35 years) and a non-ASD group of 24 children (20 boys; average age 8.10 years). The “ETS Questionnaire” focused on the detection of parental smoking habits and other ETS exposures. The concentrations of cotinine in urine were measured by ELISA kit. A significant delay in adaptive behavior of children with ASD in comparison with the non-ASD group was identified. The significant differences were in adaptive behavior, communication, and everyday skills. Children with ASD were more likely to be exposed to ETS, especially in the household. Good agreement was found between objective and subjective ETS exposure indicators (kappa = 0.613). Self-reported exposure to ETS corresponded significantly with the median levels of urinary cotinine. In addition to evaluation and assessment of the quality of adaptive behavior, an important goal of further research should be to identify, investigate, and eliminate environmental factors that interfere with adaptive behavior.

18 June 2025 in Biological Psychology
Verified
Journal Article
Closed access
IBIvan Belica
Ivan Belica
FBFilip Blasko
Filip Blasko
ISIvan Sleziak
Ivan Sleziak
KJKatarina Jansakova
Katarina Jansakova
MVMaria Vidosovicova
Maria Vidosovicova
BMBoris Mravec
Boris Mravec

28 July 2025 in Genes
Verified
Journal Article
Open access
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GRGabriela Repiska
Gabriela Repiska
MKMichal Konecny
Michal Konecny
GKGabriela Krasnanska
Gabriela Krasnanska
HCHana Celušáková
Hana Celušáková
IBIvan Belica
Ivan Belica
SLSilvia Lakatošová
Silvia Lakatošová
Background: Autism spectrum disorder (ASD) is a heterogeneous group of neurodevelopmental disorders characterized by a complex, multifactorial etiology with a strong genetic contribution. Our study aimed to evaluate the link between the burden of rare genetic variants within a specific panel of ASD and intellectual disability-associated genes and phenotypic variability in a cohort of children with autism in Slovakia. Methods: Gene burden scores were calculated based on pathogenic, likely pathogenic, and uncertain significance rare DNA variants identified by whole-exome sequencing. We then assessed the effect of three different scoring methods on the variance across 15 psycho-behavioral parameters describing the phenotypic profiles of 117 ASD probands. Results: The burden score showed a significant multivariate effect on the combination of psycho-behavioral parameters. This score was associated with the social affect of ADOS-2, as well as with the socialization domain, and total adaptive behavior scores from the Vineland Adaptive Behavior Scales-3 (VABS). While a score based solely on count of pathogenic and likely pathogenic variants did not show a multivariate effect, incorporating variants of uncertain significance revealed a multivariate effect on two adaptive behavior parameters: daily living skills and total adaptive behavior score (VABS). Conclusions: Our findings partially explain the variability in phenotypic manifestation in our ASD patient cohort, highlighting the importance of considering the cumulative effect of rare genetic variants, including those of uncertain significance, in shaping the diverse clinical presentation of ASD.

15 November 2024 in Biomedicines
Verified
Journal Article
Open access
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TJTomas Jasenovec
Tomas Jasenovec
DRDominika Radosinska
Dominika Radosinska
IBIvan Belica
Ivan Belica
BRBarbara Rašková
Barbara Rašková
APAngelika Puzserova
Angelika Puzserova
JRJana Radosinska
Jana Radosinska
Background: Multiple research teams have documented various abnormalities in erythrocyte properties in children with autism spectrum disorder (ASD) compared with neurotypical individuals. Reduced erythrocyte deformability, a crucial factor for microcirculation and oxygen delivery, may affect brain function. Other key factors like nitric oxide (NO) and Na,K-ATPase-regulated cation transport also play roles in both erythrocyte deformability and ASD, suggesting a possible relationship between erythrocyte parameters and autism severity. Thus, this study aims to describe these associations, exploring erythrocyte properties as potential biomarkers in ASD. Methods: A total of 179 ASD children were enrolled in this study. Diagnosis was confirmed by the Autism Diagnostic Observation Schedule—Second Edition (ADOS-2) and Autism Diagnostic Interview-Revised. The Vineland Adaptive Behavior Scales, Third Edition (VABS-3), was used to assess adaptive behavior. RBC deformability was measured using a filtration technique, while NO production by RBCs was assessed via DAF-2DA fluorescence. Na,K-ATPase kinetics and RBC osmotic resistance were evaluated spectrophotometrically. Results: Children with more severe ASD symptoms had more impaired deformability and osmotic resistance than children with mild symptoms. Higher RBC NO production was linked to better scores in some VABS-3 subdomains, and in the social affect domain of ADOS-2. Higher affinity of Na,K-ATPase for sodium negatively correlated with the occurrence of repetitive and restricted behavior—one of the core ASD symptoms. Conclusions: This study identified potential links between ASD severity and RBC properties. While erythrocyte quality can influence ASD symptomatology, the observed relationships—such as those involving RBC deformability, NO production, Na,K-ATPase kinetics, and osmotic resistance—were not strong or consistent enough to be considered reliable diagnostic or prognostic biomarkers.