Aggressive treatment to control high blood pressure and diabetes before age 60 can significantly reduce the risk of a decline in mental ability associated with these disorders, according to the results of a recently published large-scale study.

 Introduction

Declining mental function in older individuals with high blood pressure and diabetes may be due to small changes that begin in middle age and accumulate over several years or decades. Studies have shown that people with high blood pressure and diabetes in middle age are at greater risk for declining mental function in elderly years. However none of these studies has actually measured mental function in middle-age people with these diseases. And none of them has been a large-scale study that has looked at changes in mental ability over a period of time. The study summarized here assessed the mental ability of middle-age people with high blood pressure and diabetes who were participating in a large cardiovascular trial over a 6-year period.

Methods

Researchers studied close to 11,000 (8,700 white and 2,300 black) individuals ages 47 to 60 over a six-year period who were participants in the Atherosclerosis Risk in Communities study organized by physicians from the Mayo Clinic, Rochester, Minnesota. At the beginning (baseline) of the study, researchers administered three standard assessments that tested the subjects' ability to learn and recall given words, translate numbers to symbols using a key provided, and generate words beginning with the letters A, F and S. The tests were repeated six years later, at the end of the study.

Researchers also assessed the following risk factors at baseline: high blood pressure, diabetes and high low-density cholesterol levels (LDL cholesterol), smoking, use of non-prescription and prescription drugs, and the thickness of the carotid artery wall.

Subjects' baseline and six-year test scores were compared to determine whether there was any change over the study period. The changes in test scores were also compared to the risk factors.

Results

The average score for all study participants decreased over the six-year study period. However, the changes were small and were greater for older than younger individuals. More importantly...

• People with diabetes had the greatest decrease in their test scores. This decrease was statistically significant.
• When the subjects were divided into a "younger" (age 47-57) and an "older" (age 58-70) age group, the decrease in test scores was significant for both age groups with diabetes.
• For individuals with high blood pressure, the test score declines were only significant for people age 58 -70.

Other risk factors - carotid artery wall thickness, smoking, elevated LDL cholesterol and use of non-steroidal anti-inflammatory drugs and CNS drugs was not associated with declines in test scores.

Conclusions

High blood pressure and diabetes are associated with a decline in cognitive function (mental ability) in middle-aged and young-elderly. The changes measured by the tests in this study were so small that they most likely were unnoticed by the study participants. The researchers conclude, however, that these finding suggest the need for aggressive diagnosis and treatment of high blood pressure and diabetes. Small, sub-clinical changes over time can result in impaired mental function later in life.

Source

Cardiovascular risk factors and cognitive decline in middle-aged adults. D. Knopman, LL. Boland, T. Mosley,  et al., Neurology, 2001, vol. 56, pp. 42--48

Links

• Can diabetes trigger Alzheimer's disease?

Beat you risk factors. Charlotte Libov