Associations of polysocial risk score, lifestyle and genetic factors with incident type 2 diabetes: a prospective cohort study

We aimed to investigate the association between polysocial risk score (PsRS), an estimator of individual-level exposure to cumulative social risks, and incident type 2 diabetes in the UK Biobank study. This study includes 319,832 participants who were free of diabetes, cardiovascular disease and cancer at baseline in the UK Biobank study. The PsRS was calculated by counting the 12 social determinants of health from three social risk domains (namely socioeconomic status, psychosocial factors, and neighbourhood and living environment) that had a statistically significant association with incident type 2 diabetes after Bonferroni correction. A healthy lifestyle score was calculated using information on smoking status, alcohol intake, physical activity, diet quality and sleep quality. A genetic risk score was calculated using 403 SNPs that showed significant genome-wide associations with type 2 diabetes in people of European descent. The Cox proportional hazards model was used to analyse the association between the PsRS and incident type 2 diabetes. During a median follow-up period of 8.7 years, 4427 participants were diagnosed with type 2 diabetes. After adjustment for major confounders, an intermediate PsRS (4–6) and high PsRS (≥7) was associated with higher risks of developing type 2 diabetes with the HRs being 1.38 (95% CI 1.26, 1.52) and 2.02 (95% CI 1.83, 2.22), respectively, compared with those with a low PsRS (≤3). In addition, an intermediate to high PsRS accounted for approximately 34% (95% CI 29, 39) of new-onset type 2 diabetes cases. A healthy lifestyle slightly, but significantly, mitigated PsRS-related risks of type 2 diabetes (pinteraction=0.030). In addition, the additive interactions between PsRS and genetic predisposition led to 15% (95% CI 13, 17; p<0.001) of new-onset type 2 diabetes cases (pinteraction<0.001). A higher PsRS was related to increased risks of type 2 diabetes. Adherence to a healthy lifestyle may attenuate elevated diabetes risks due to social vulnerability. Genetic susceptibility and disadvantaged social status may act synergistically, resulting in additional risks for type 2 diabetes.