Environmental Determinants and Triggers of Type 1 Diabetes Incidence Among Children and Adolescents in Europe: A Narrative Review

Type 1 diabetes (T1D) is one of the most common chronic diseases in childhood and adolescence, and Europe includes some of the populations most affected worldwide. However, pediatric T1D incidence varies markedly across Europe, suggesting that genetic susceptibility alone cannot explain these disparities. While T1D environmental determinants and European epidemiological trends have each been reviewed separately, fewer narrative syntheses have integrated recent incidence patterns, trigger hypotheses, COVID-19-era observations, and gene–environment interpretations within a single pediatric public health perspective. This narrative review aims to summarize regional differences in pediatric T1D incidence across Europe and discuss the environmental, socioeconomic, and gene–environment determinants that may contribute, based on a targeted literature search prioritizing European registries, multicenter studies, prospective birth cohorts, systematic reviews, and meta-analyses. Environmental determinants considered include perinatal and early-life exposures, breastfeeding and infant nutrition, growth patterns, vitamin D and sunlight, viral infections including SARS-CoV-2, microbiome/exposome-related factors, urbanization, air pollution, endocrine-disrupting chemicals, and socioeconomic conditions. Evidence is heterogeneous and largely observational. Enteroviruses and early growth patterns show relatively consistent prospective and biological support, whereas evidence for most nutritional, chemical, environmental, and socioeconomic exposures remains less consistent and does not establish causality. Pediatric T1D in Europe is best understood through a multifactorial gene–environment model. Harmonized registries, prospective birth cohorts, and integrated genetic–exposomic approaches are needed to clarify causal pathways, identify modifiable exposures, and inform prevention and early-diagnosis strategies.