WASHINGTON -- Low blood pressure correlated with Alzheimer's disease among 3,734 elderly men, but the dementia appeared to be attributable to the presence of other chronic diseases and not hypotension itself.

Other studies have found that hypertension in midlife can predict dementia, but

Dr. Gina Fujikami led the study during her just-completed fourth year as a medical student at the University of Hawaii at Manoa.

She and her colleagues reviewed data from the Honolulu-Asia Aging Study, ongoing since 1991. At entry to the study, the men, all Japanese Americans aged 71-93 years, were given physical examinations, screened for Alzheimer's disease and other dementias, and evaluated using the Cognitive Abilities Screening Instrument. They were reexamined after 3 years and again after 6 years.

For the analysis, systolic blood pressure was divided into four categories: less than 120 mmHg, 120-139 mmHg (defined as normal), 140-159 mmHg, and 160 mmHg or higher. Diastolic blood pressure was divided into three categories: less than 80 mmHg, 80-89 mmHg, and 90 mmHg or higher.

The researchers looked for associations between blood pressure categories and cognitive status in the men at each of the three examinations. The team also traced changes in blood pressure and cognitive function over the 6-year period.

The prevalence of dementia at the beginning of the study was 6%, and only Alzheimer's dementia correlated with a blood pressure category: below-normal systolic pressure. Men with systolic blood pressure less than 120 mmHg at the study's onset were more than twice as likely to have Alzheimer's disease, but not other dementias, than were men with normal systolic pressure.

The association emerged after the researchers controlled for variables including age, smoking, and other diseases. But the men who had low systolic blood pressure appeared to be sicker than others, the team

noted.

The researchers then further analyzed results from men who had at least one chronic disease, such as diabetes or coronary heart disease, versus those free of chronic disease. The increased prevalence of Alzheimer's disease again emerged among men with chronic diseases and low systolic blood pressure, but the association was lost among the healthier study participants, Dr. Fujikami said in her report of the study at the annual meeting of the American Geriatrics Society.

"In our study, we found that low blood pressure reflected a state of chronic disease and frailty, which may account for the association with dementia," said Dr. Fujikami.

She stated that she and her colleagues had no financial conflicts of interest relevant to the study.

BY HEIDI SPLETE

Senior Writer