Do poor psychosocial resources mediate health inequalities in type 2 diabetes mellitus? Findings from the Maastricht study

Low socioeconomic position (SEP) has been identified as a risk factor for type 2 diabetes mellitus (T2DM), and psychosocial resources might be on the pathway in this association. We examined two poor psychosocial resources, low control beliefs and inferiority beliefs, that might link low SEP with T2DM. 8292 participants aged 40-75 living in Southern Netherlands participated in The Maastricht Study starting from September 2010 to October 2020 and were followed up to 10 years with annual questionnaires. SEP (education, income, occupation), low control beliefs, inferiority beliefs, and (pre)diabetes by oral glucose tolerance test were measured at baseline. Incident T2DM was self-reported per annum. We analysed the mediating roles of poor psychosocial resources by using counterfactual mediation analysis. People with low SEP had more often prevalent and incident T2DM (e.g. low education: HR = 2.13, 95%CI: 1.53-2.97). Low control beliefs and high inferiority beliefs were more common among people with low SEP. Moreover, low control beliefs and high inferiority beliefs were risk factors for T2DM (e.g. low control beliefs: HR = 1.50, 95%CI: 1.08-2.09). The relationship between SEP and T2DM was partially mediated by control beliefs (8.0-13.6%) and inferiority beliefs (2.2-4.5%). We conclude that poor psychosocial resources are important in socioeconomic inequalities in diabetes. Researchers and practitioners should consider the psychosocial profile of people with lower SEP, as such a profile might interfere with the development, treatment, and prevention of T2DM. Further research should explore how poor psychosocial resources interact with chronic stress in relation to socioeconomic health inequalities.