An Intersectional Perspective on Onset of Type 2 Diabetes in Adults aged 50 and older in Europe: A Multilevel Analysis of Individual Heterogeneity and Discriminatory Accuracy

Abstract Background: Disparities in the development of Type 2 Diabetes (T2D) are associated with various social determinants, including sex/gender, migration background, living arrangement, education, and household income. However, few quantitative studies have applied an intersectional perspective to examine non-additive effects of overlapping social identities. This study aimed to map social disparities and investigate intersectional effects regarding the onset of T2D among older adults across Europe. Methods: We used data from the Survey of Health and Retirement in Europe (SHARE) to conduct an intersectional Multilevel Analysis of Individual Heterogeneity and Discriminatory Accuracy (MAIHDA) of T2D onset. Individuals aged 50 years or older without known T2D at wave 4 (2011, baseline) were included and followed through waves 5 (2013), 6 (2015), 7 (2016), and 8 (2019-2020). A series of multilevel logistic regression models were run with individuals nested in 72 social strata based on intersections of sex/gender, migration background, living arrangement, education level, and household income. Intersectional models were used to estimate additive main effects and intersectional interactions, while adjusting for age and country. Results: A total of 39,108 individuals were included (age at baseline in years M=65.18 (SD=9.62), 57.4% women). T2D onset was reported for 9.2% of the sample over the 9-year observation period. In the fully adjusted model, all social determinants showed significant additive associations with T2D onset, while the discriminatory accuracy of the social strata was found to be low (Variance Partition Coefficient=0.3%). Conclusions: This study provides a comprehensive mapping of disparities in onset of T2D among older adults in Europe. While the results highlight disadvantages faced by certain groups based on social determinants, we found no evidence of multiplicative (i.e., intersectional) effects. Healthcare professionals and public health initiatives should consider the unique challenges faced by individuals with diverse social identities to effectively address the prevention and management of T2D.