Objectives: Type 2 diabetes (T2DM) is strongly associated with cognitive impairment but the factors within T2DM that predispose to cognitive impairment are less well understood, while previous studies have investigated samples with T2DM of widely varying duration. We aimed to investigate the factors associated with cognitive impairment in patients with newly diagnosed T2DM.
Method: In a multi-ethnic sample with T2DM diagnosed in the last 6 months, we assessed cognitive function using the 13-item modified telephone interview for cognitive status (TICS-M). Cognitive function was assessed both categorically (impairment defined as lowest 10% of scores with the remainder as controls) and as continuous TICS-M score. Its associations were tested in univariate and multivariate analyses with a range of biological, psychological and sociodemographic factors.
Results: Of 1790 participants, 1680 had a complete TICS-M assessment at baseline. After controlling for covariates, older age (p < 0.001) and lower verbal intelligence (p < 0.001) were associated with both cognitive impairment and lower TICS-M scores, while non-white ethnicity (p < 0.001), female gender (p = 0.02) and higher HbA1c (p = 0.002) were associated with lower TICS-M scores. Depression (defined as Patient Health Questionnaire-9 score ≥10), elevated inflammatory markers and body mass index were not associated with cognitive function after controlling for covariates.
Conclusion: Age, verbal intelligence, female gender and HbA1c are associated with cognitive performance in T2DM soon after diagnosis. Previously reported associations with depression and inflammatory markers may occur later as causes or consequences of T2DM. Longitudinal analyses are needed to assess potentially modifiable factors predicting cognitive decline in early T2DM.
Keywords: cognitive impairment; diabetes; ethnicity; glycaemic control; verbal intelligence.