Beyond Soil Selenium: Agroindustrial Exposure Pathways and Diabetes Risk Assessment in Contemporary China

A recent multicenter Chinese cohort study reported a prospective association between high serum selenium (Se) status and incident type 2 diabetes (T2D), while interpreting regional serum Se variation largely through local soil geochemistry. Although the correlation between soil and serum Se is robust at the regional scale, the inferential leap from geochemistry to dietary exposure may underestimate contemporary food system inputs. Two structural features of modern China, institutionalized Se supplementation in compound feed since 2009 and large-scale importation of soybean meal from geochemically heterogeneous origins, have introduced agroindustrial Se pathways that may partially decouple animal-source dietary Se from local soils. Risk mapping based solely on geochemical proxies may misclassify exposure burden in regions where these pathways dominate. Future Se exposure assessments should integrate geochemical, dietary, food supply chain, environmental, and biomarker data, particularly for populations with serum Se levels comparable to the highest tertile in that cohort.