Severe Illness Linked To Lower Mental Ability In 'Young Olds'
High blood pressure can lead to declines in some mental abilities over and above those associated with advancing age, according to researchers who examined 140 men and women over two decades.
"Elevated blood pressure, across the full range of BP values, is a risk factor for structural and functional changes in the brain," says lead researchers Merrill F. Elias, PhD, of the University of Maine, Orono. "Clearly, elevated BP is a strong predictor of changes in brain structure and related cognitive functioning."
Elias and colleagues examined blood pressure and mental function in 140 men and women 40 to 70 years old. At the beginning, and again approximately every five years over the following two decades, participants returned to the lab to have repeated blood pressure assessments. They also completed the Wechsler Adult Intelligence Scale, which measures a variety of cognitive abilities, including verbal comprehension, visual-spatial abilities, memory, and speed of performance.
Writing in the November issue of Health Psychology, the researchers report that all participants did more poorly on the intelligence test over time, whether or not they met criteria for hypertension at any time during the study.
More important in predicting intelligence test scores was the participants' average blood pressures over time. Higher levels were generally associated with greater declines, particularly for tests of visual-spatial ability and speed of performance. When the researchers statistically controlled for the participants' age, the effect remained but was less strong.
Although the researchers did not screen for the full range of coexisting medical diseases, their study participants had no obvious cardiovascular complications and remained generally in good health over the course of the study.
"Clearly undetected disease or subclinical consequences of hypertension and pathology related to extreme variations in blood pressure are plausible links between elevated blood pressure and accelerated declines in cognitive functioning over time," Elias says.
The research was supported by grants from the National Institute on Aging. In a related report in the same issue of Health Psychology, Elizabeth M. Zelinski, PhD, and colleagues at the University of Southern California, Los Angeles, say that several medical conditions have a greater effect on the mental abilities of 'young old' adults than on the 'oldest old.' Nearly 6,500 men and women from 70 to 103 years old were tested on their ability to recall lists, do mental arithmetic, and identify words given their definition. Stroke was associated with poorer performance on all three tests, the researchers found, while diabetes, hypertension, and poor health in general were linked with lowered performance on at least two tests.
The effects of these medical conditions were generally strong among the youngest older adults in the sample, and 'smaller or non-existent for the oldest old,' the researchers say. "Those who survive into extreme old age may have less severe conditions than those who are younger."
"Programs to prevent stroke, diabetes, and high blood pressure, as well as to promote good health, are relevant to the goal of keeping the oldest-old Americans from experiencing cognitive deficits that may affect the quality of their lives," the researchers conclude.
NOTE: Dr. Elias can be reached at (207) 581-2097, mfelias@maine.maine.edu; Dr. Zelinski can be reached at (213) 740-4918; zelinski@rcf.usc.edu
Health Psychology is the official, peer-reviewed research journal of the Division of Health Psychology (Division 38), American Psychological Association.
Posted by the Center for the Advancement of Health http://www.cfah.org.
For information about the Center contact Richard Hebert rhebert@cfah.org, (202) 387-2829.
Journal
Health Psychology