OBJECTIVES: In 2021, approximately 8.4 million people worldwide were diagnosed with type 1 diabetes. The incidence of type 1 diabetes is increasing at an average annual rate of 2-5% in pediatric populations, suggesting it is a public health priority. Identifying and understanding the influence of external factors on the etiology of type 1 diabetes is essential for effective screening and prevention of the disease. Therefore, a targeted literature review was conducted to provide an overview of the published literature on environmental and socio-demographic factors associated with onset of type 1 diabetes.

METHODS: An electronic search strategy was run in May 2024 in Medline and Embase to capture narrative and systematic reviews reporting on environmental or socio-demographic factors associated with onset of type 1 diabetes. 669 review articles were independently screened by 2 reviewers against PICOS criteria, and the reference lists of reviews that met all PICOS criteria were searched to identify robust observational studies published in the last 10 years reporting environmental and socio-demographic factors associated with onset of type 1 diabetes. Supplemental hand searching was also performed.

RESULTS: 22 studies using several national and international databases were included from various geographical locations, including Europe, North America, the Middle East, Africa, Australasia, and the UK. Environmental factors associated with onset of type 1 diabetes included population density, air pollution, pesticide exposure, land cover, infections (including Coxsackievirus and COVID-19), vaccination, and gut microbiota. Socio-demographic factors associated with onset of type 1 diabetes included sex, race, social deprivation, socioeconomic status, education level, and employment status.

CONCLUSIONS: This review identified a multitude of environmental and socio-demographic factors associated with onset of type 1 diabetes, from wide-ranging geographies. These factors may help to explain the increasing incidence of type 1 diabetes and are essential to understand for the effective prevention of the disease.