Rural children more at risk of diabetes, study reveals

Rural areas have a higher risk of contracting the disease for those under 5, while city life can be a shield.

Rural children are more likely to develop diabetes than their city-dwelling peers. This is the surprising finding of Samy Sebraoui, Soffia Gudbjornsdottir, and colleagues from the University of Gothenburg in Sweden, authors of a study that will be presented at the Annual Congress of the European Association for the Study of Diabetes (EASD), scheduled for September 15-19 in Vienna, Austria. " Living in rural, rather than urban, environments in the first 5 years of life could be a risk factor for developing type 1 diabetes ," the researchers conclude, advancing a hypothesis yet to be confirmed: "Viral infections more common in city children could protect against future autoimmune diseases, including type 1 diabetes." Conversely, "living in the countryside could be associated with greater exposure to pesticides and allergens, for example," which could make them more vulnerable to autoimmune diseases.

Sweden has the second highest incidence of type 1 diabetes globally , with geographic variations suggesting environmental risk factors. Previous studies have focused on the location of newly diagnosed patients, while very few have considered the address of residence at birth or before diagnosis. According to data collected by scientists, 21,774 children and young people aged 0 to 30 were diagnosed with type 1 diabetes from 2005 to 2022. Fifty-eight percent were male, and approximately three out of four were under 18 when the disease was discovered. The average age at diagnosis was 13.6 years (men 14.1, women 12.9), and 24% of patients had moved to a different municipality between birth and before diagnosis.

Based on the patients' location at diagnosis, the authors identified four geographic clusters where the risk of developing type 1 diabetes was 30–80% higher than expected based on national averages: all clusters were located in the countryside, far from urban centers. Among urban residents, no high-risk clusters for type 1 diabetes were observed ; indeed, low-risk clusters were found in larger cities, with a 20–50% lower probability of developing type 1 diabetes. A second analysis based on place of residence in the first 5 years of life identified 11 high-risk clusters, all rural, with a probability of developing type 1 diabetes increased from 20% to 2.7 times compared to national averages. Fifteen low-risk clusters were also identified, all in cities, where the chances of developing type 1 diabetes were 20–88% lower. The high-risk clusters were characterized by agricultural or forested land, while the low-risk clusters were dominated by urban and open land.

"There is clear geographic variation in the incidence of type 1 diabetes in Sweden, and the first 5 years of life showed the strongest association with high- and low-risk clustering," the researchers comment. "Our findings," they emphasize, "encourage further research into environmental factors that potentially influence the development of type 1 diabetes. We hypothesize that exposure to environmental factors, predominantly in rural areas and primarily during the first 5 years of life, increases the risk of developing type 1 diabetes."

"These findings were previously unknown and unexpected," the authors add. "It was surprising to find that living in larger cities resulted in a lower future risk of type 1 diabetes. We will study in detail several environmental factors that may have a protective effect or increase risk. We will also examine the different lifestyles in urban versus rural areas."