Autoantibody screening in children who are first-degree relatives of individuals with type 1 diabetes in a sibling-dominant cohort in Turkey: a multicentre study on prevalence, determinants and post-screening parent-child anxiety.

AIMS/

objectiveWe screened 2-18-year-old first-degree relatives (FDRs) of individuals with type 1 diabetes in Turkey for diabetes-associated autoantibodies to define their prevalence and age distribution, to identify determinants of autoantibody positivity, and to quantify acute anxiety changes in children and parents after result disclosure.

methodsIn this multicentre cross-sectional study conducted across nine paediatric endocrinology centres in Turkey, 440 FDRs aged 2-18 years were screened. Affected FDR relationships included an affected sister (n=206), brother (n=204), mother (n=22) and father (n=13). ZnT8A, GADA, IAA and IA-2A autoantibodies were measured by ELISA; perinatal variables including gestational age were recorded. In the 8-18-year-old subsample, child anxiety was assessed using the full Screen for Child Anxiety Related Emotional Disorders (SCARED) and parental anxiety for these children was assessed using the State-Trait Anxiety Inventory (STAI-I/II), administered before screening and immediately after disclosure.

resultsThe proportion of participants who were autoantibody-positive was 16.4% (72/440), and multiple autoantibodies were detected in 13 individuals (3.0%). Among 445 affected FDR relationships, 92.1% were sibling-based and 7.9% were parent-based. ZnT8A was the most common autoantibody (11.4%) and predominated at ages 2-6 years (82% of autoantibody-positive children), declining with age. ZnT8A positivity showed an age-dependent decline, with ZnT8A-positive participants being significantly younger than ZnT8A-negative participants (7.92 ± 4.62 vs 10.00 ± 4.54 years; p=0.002). Each additional week of gestational age was associated with lower odds of autoantibody positivity (adjusted OR 0.80 per week; 95% CI 0.68, 0.93; p=0.005). This association persisted and was strengthened after exclusion of participants with an affected mother (adjusted OR 0.71 per week; 95% CI 0.59, 0.85; p<0.001). SCARED scores increased after disclosure in autoantibody-positive children (d=1.31; p<0.001) but decreased in autoantibody-negative children (d=0.62; p<0.001). Parental anxiety increased after positive results (state d=2.19; p<0.001; trait d=0.69; p=0.001) and decreased after negative results (p<0.001). CONCLUSIONS/

interpretationThe ZnT8A predominance in early childhood and the independent association of gestational age with autoantibody positivity support integrating age and perinatal history into presymptomatic risk stratification. These findings should be interpreted primarily within the context of a sibling-dominant paediatric FDR screening cohort. The marked outcome-dependent anxiety response indicates that screening programmes should pair immunological testing with structured, result-specific counselling, integrating psychological support protocols that address differential parent-child anxiety responses with child-appropriate assessment.