ESSENTIAL-HYPERTENSION AND COGNITIVE FUNCTION - THE ROLE OF HYPERINSULINEMIA

The relation between hypertension and cognitive function is not well e stablished. Therefore, we examined cognitive function in a random samp le of 744 nondiabetic elderly inhabitants of Kuopio, East Finland. Fiv e brief neuropsychological tests known to be sensitive to cognitive im pairment due to dementia-the Mini-Mental State Examination (MMSE), the Trail Making Test (TMT), the Buschke Selective Reminding Test (BSR), Russell's Adaptation of the Visual Reproduction Test (HVR), and the Ve rbal Fluency Test (VFT) - were used to evaluate cognitive function. Th e performance of the hypertensive group (n=378) was impaired in almost all test items compared with that of the normotensive group (n=366), but the difference between these two groups was statistically signific ant in 5 of 19 test items only. Moreover, within the hypertensive grou p, hyperinsulinemic (fasting plasma insulin >17.9 mU/L) hypertensive s ubjects (n=57) scored worse than normoinsulinemic hypertensive subject s (n=321) in 16 of 19 test items and worse than the normotensive subje cts in the same 16 of 19 test items. The difference between the hyperi nsulinemic hypertensive and normotensive groups was significant in 11 test items that reflected complex cognitive function such as calculati on, language, semantic memory, and problem solving. This difference in neuropsychological tests among the three study groups (normotensive, normoinsulinemic hypertensive, and hyperinsulinemic hypertensive subje cts) persisted after adjustment for fasting plasma glucose, age, sex, and education in 3 test items measuring calculation, copying, and sema ntic memory. Thus, essential hypertension in the elderly is associated with an impairment in complex cognitive function. Furthermore, hyperi nsulinemia seems to identify a subgroup of hypertensive subjects with a particularly poor performance in neuropsychological tests requiring complex cognition such as semantic memory, problem solving, and abstra ction.