Hypertension, blood pressure, cognition and cerebral blood flow in the cohort of "Men born 1914"

Sammanfattning: "Men born 1914" is a population based cohort study of the epidemiology of cardiovascular disease. Five hundred men, born 1914, were examined at the age of 68 and 185 of them were re-examined at 81 years of age. Examination included a medical and a psychological investigation, ultrasonographic measurement of carotid arteries, 24-hour ambulatory blood pressure monitoring, regional cerebral blood flow, and cardiovascular risk factors. It is well known that hypertension plays a major etiological role in the development of cerebrovascular disease, ischemic heart disease, and cardiac failure. High blood pressure has often been discussed as a risk factor in regard to cerebrovascular disorders and even vacular dementia and over the years much research has been performed to study elevated blood pressure, its treatment and prevention. Active treatment of hypertension substantially reduces the risk of these complications. However, very little attention has been paid to low blood pressure and diurnal variation of blood pressure in the elderly. It is well known that a fall in blood pressure may lead to cerebral hypoperfusion and might be of importance in the development of cerebrovascular insufficiency, i.e. those in which the cerebral blood flow is inadequate in relation to the metabolic needs of the brain tissue. The resultant decrease in the cerebral blood flow gives rise to ischemic hypoxia. Study I showed, that hypertension is a potential risk factor for the development of carotid artery stenosis (CAS). 93% of the surviving study cohort had CAS at 81 years of age. Study II showed, that high blood pressure at baseline examination, especially DBP and decrease of DBP, was inversely related to speed performance and spatial functions in psychometric tests taken 13 years later. Study III showed significant associations between blood pressure (BP) levels and cerebral blood flow (CBF), especially at night. The noted association between rCBF and low BP might indicate an increased risk for nocturnal cerebral ischemia. Study IV showed, that extreme blood pressure fall at night in a cohort of elderly men is associated with focal changes in cerebral perfusion. This could be correlated with increasing blood pressure over a long time and result in damage of vascular autoregulation.