AHA News
11/19/2007

High blood pressure increases risk of reduced function in older age

High blood pressure significantly increases the risk of disabilities later in life, such as the inability to lift objects, walk up or down stairs, or bathe oneself — all essential to living an independent daily life, researchers reported in Hypertension: Journal of the American Heart Association.

“This adds another dimension to how we think about hypertension,” said Ihab Hajjar, M.D., lead author of the study.  “We always think of it as a risk factor for stroke, heart failure, kidney failure and coronary artery disease.  But this study shows elevated blood pressure, specifically systolic blood pressure, also tends to affect our independence and functional abilities.”

Systolic pressure is the top number in a blood pressure reading, representing the pressure when the heart contracts.  A systolic pressure at or above 140 millimeters of mercury (mm Hg) is considered hypertension or high blood pressure.   The bottom number is the diastolic pressure, representing the blood pressure when the heart relaxes.   Diastolic pressure at or above 90 mm Hg is considered hypertension.

Nearly one in three American adults has high blood pressure and more than 65 percent of older adults have the disorder.   The incidence of high blood pressure is increasing in women, and the study found that women with hypertension face a higher risk of disability than hypertensive men.

“It is very important for clinicians who are managing young and old patients with hypertension to counsel them about their risks of disability, if their blood pressure is elevated,” said Hajjar, an instructor in medicine at Harvard Medical School and an associate scientist at the Institute for Aging at Hebrew Seniorlife and Beth Israel Deaconess Medical Center in Boston, Mass.

Researchers analyzed data from the Charleston Heart Study, which began in South Carolina in 1960 and collected its last survival data in 2001.   In this study, researchers investigated hypertension as a potential reason for why people age differently.   They chose the Charleston Heart Study because of its extensive available data, its location in the southeastern United States, which has a high incidence of hypertension, and because 39 percent of participants were African Americans.

“Prior studies, most notably the Framingham Heart Study, enrolled mostly Caucasians, and as we know, African Americans tend to be affected by cardiovascular disease more than any other group,” Hajjar said.

He and his colleagues analyzed data from 999 study participants.   Seventy percent of them had hypertension but only 21 percent of those had their blood pressure controlled to optimal levels.

None of them had ever suffered a stroke prior to 1984-85, when they underwent their first of three follow-up evaluations that included disability assessments.

Patients answered three standard questionnaires that gauged their upper and lower body strength, motor skills, physical mobility and ability to perform daily activities.

The researchers classified study members as normal (a blood pressure less than 140/90 mm Hg without using blood pressure drugs) or hypertensive (a systolic pressure at or above 140/90 mm Hg or taking medications to control blood pressure).  They also divided the hypertensive patients into two groups: controlled – a blood pressure kept below 140/90 mm Hg with medications – or uncontrolled, if the pressure was140/90 mm Hg or higher.  

Researchers then examined what it termed remote blood pressure change — which is the change in blood pressure between 1960 and 1984-85 — and concurrent, the change in blood pressure between 1984-85 and 1987-90 and 1990-93.   Disability was measured in 1984-85 and 1990-93.

Among the study’s key results:

• People with hypertension had greater declines in all three functional measures than those with normal blood pressure.
• A greater increase in either remote or concurrent systolic blood pressure was associated with a greater decline in all three functional measures. 
• People with hypertension but without disability in 1984-85 had an increased risk of developing one of the three types of disabilities, ranging from 15 percent to 36 percent, by their third and final follow-up, compared to people with normal blood pressure.
• The researchers found no consistent differences in disability risk associated with age, race, obesity or medical disorders.
• Compared to men, women with hypertension had a significant increased risk of developing disabilities from hypertension related to physical mobility and the ability to perform daily activities, but not related to their upper and lower body strength and motor skills.

“It’s really hard to explain why women may be at increased risk for disability from hypertension, but it’s an important area to explore,” Hajjar said.  “The number of women with hypertension has increased significantly over the last 10 to 20 years.   That would translate into a significant degree of disability in the future.”

Co-authors are: Daniel Lackland, Ph.D.; L. Adrienne Cupples, Ph.D.; and Lewis A. Lipsitz, M.D.

The National Institutes of Health and the National Institute on Aging partially funded this study.

Editor’s note: The American Heart Association has a Web site dedicated to the prevention and management of high blood pressure.   For more information visit americanheart.org/hbp.

Statements and conclusions of study authors that are published in the American Heart Association scientific journals are solely those of the study authors and do not necessarily reflect association policy or position.  The American Heart Association makes no representation or warranty as to their accuracy or reliability.

NR07 – 1245 (Hyp/Hajjar)

####