Lower verbal intelligence is associated with diabetic complications and slower walking speed in people with Type 2 diabetes: the Maastricht Study

Aims To determine the association of verbal intelligence, a core constituent of health literacy, with diabetic complications and walking speed in people with Type 2 diabetes. Methods This study was performed in 228 people with Type 2 diabetes participating in the Maastricht Study, a population‐based cohort study. We examined the cross‐sectional associations of score on the vocabulary test of the Groningen Intelligence Test with: 1) determinants of diabetic complications (HbA1c, blood pressure and lipid level); 2) diabetic complications: chronic kidney disease, neuropathic pain, self‐reported history of cardiovascular disease and carotid intima‐media thickness; and 3) walking speed. Analyses were performed using linear regression and adjusted in separate models for potential confounders and mediators. Significant age‐ and sex‐adjusted associations were additionally adjusted for educational level in a separate model. Results After full adjustment, lower verbal intelligence was associated with the presence of neuropathic pain [odds ratio (OR) 1.18, 95% CI 1.02;1.36], cardiovascular disease (OR 1.14, 95% CI 1.01;1.30), and slower walking speed (regression coefficient −0.011 m/s, 95% CI −0.021; −0.002 m/s). These associations were largely explained by education. Verbal intelligence was not associated with blood pressure, glycaemic control, lipid control, chronic kidney disease or carotid intima‐media thickness. Conclusions Lower verbal intelligence was associated with the presence of some diabetic complications and with a slower walking speed, a measure of physical functioning. Educational level largely explained these associations. This implies that clinicians should be aware of the educational level of people with diabetes and should provide information at a level of complexity tailored to the patient. What's new? This cohort study is the first to examine the associations of verbal intelligence with diabetic complications and walking speed in people with Type 2 diabetes. Lower verbal intelligence was associated with the presence of neuropathic pain and cardiovascular disease, and with slower walking speed, a measure of physical functioning. Educational level seemed to play an important role in these associations It is important for clinicians to be aware of the educational level of their patients with diabetes so as to tailor the information to a level that can be understood.