During the follow-up period, 334 individuals developed mild cognitive impairment. This included 160 cases of mild amnestic decline, which is associated with low scores on memory portions of the cognitive tests, in addition to 174 cases of non-amnestic cognitive decline.
Hypertension or high blood pressure was found to be associated with an increased risk non-amnestic cognitive impairment, but did not appear to be associated with a change in memory or language abilities. The authors of the study speculate on the mechanisms behind the association. They believe hypertension may cause cognitive impairment through cerebrovascular disease.
Hypertension may also contribute to a blood-brain barrier dysfunction or be a risk factor for subcortical white matter lesions both associated with Alzheimer's disease. The authors conclude by saying, "Preventing and treating hypertension may have an important impact in lowering the risk of cognitive impairment."