Our data, and data from other investigators, should provide an additional incentive for people to control hypertension, diabetes, cigarette smoking and obesity through good health practices or medical treatment. In the Maine-Syracuse project, researchers asked participants to recall diverse materials presented to them, ranging from strings of numbers to short stories to complex figures. Various other tests required solving arithmetic problems, providing definitions for words, listing as many words as possible starting with a specific letter, identifying some likeness between apparently dissimilar objects, producing designs, and performing motor tasks with and without visual reference. As demonstrated through these neuropsychological tests, the decline in thinking abilities is gradual over time. We are talking about hypertension and diabetes as insidious predictors of gradual and subtle decline in cognitive ability.
Pathophysiological changes associated with hypertension and diabetes take many years.
So do the cognitive changes associated with them. Taken from the perspective of the individual, the individual with untreated or poorly controlled hypertension, particularly in the presence of diabetes, obesity, and smoking, may decline more in cognitive ability over time than they would if they were free from risk factors. The team of researchers controlled statistically for factors such as age, sex and medication to minimize the chances that the analysis could reflect differences in those areas. They also eliminated from the study people who had suffered a heart attack, stroke, brain trauma, psychiatric illness or dementia. Pathophysiological changes in the brain associated with diabetes are similar, and thus, you would expect both to exert a negative impact on cognitive ability, and they do.