Arterial stiffness and cognition in elderly persons with impaired glucose tolerance and microalbuminuria

Abstract

Background. Cognitive decline that occurs frequently in impaired glucose tolerance (IGT) may be largely due to endothelial dysfunction. We assessed: (i) the relationships between impact of urinary albumin excretion rate (UAER), as marker of generalized endothelial dysfunction, and cognition; (ii) if cognitive decline could be explained by arterial stiffening using pulse wave velocity (PWV). Methods. One hundred forty older patients (age range 70-85 years) with IGT and no dementia were selected. Patients were classified according to 24-hour UAER: normoalbuminuric (NA) (UAER < 20 μg/min) or microalbuminuric (MA) (UAER between 20 and 199 μg/min). Cognitive abilities were assessed by the Mini-Mental State Examination (MMSE) and a composite score of executive and attention functioning (CCS) at baseline and after 12 months of follow-up. Results. In MA patients (n = 80), increased UAERs correlated with intimal media thickness (IMT) (r = 0.268; p = .02) and PWV (r = 0.310; p = .004). In the same group, increased UAERs were correlated with MMSE and CCS even after adjusting for age and mean arterial blood pressure (MABP). After adding PWV, the associations among UAERs, MMSE, and CCS were no longer significant. In MA patients, PWV correlated with IMT, MMSE, and CCS. In NA patients, no significant correlations were found among UAERs, MMSE, and CCS. At follow-up, baseline UAERs predicted an approximately 20% risk of poor cognition (according to MMSE and CCS) after adjusting for confounders. After adding PWV, UAERs no longer predicted cognitive performance. Conclusions. MA older persons with IGT showed a decline in cognition performance that may be partially explained by arterial stiffness. Copyright 2008 by The Gerontological Society of America.