Study Finds Nearly 60 Percent Of American Adults May Have Elevated Blood Pressure

The finding, reported in the Oct. 25 issue of the Archives of Internal Medicine, comes from nationally representative health data analyzed by two University of Illinois at Chicago researchers.

Youfa Wang, an assistant professor of human nutrition and Qiong Joanna Wang, a biostatistician at UIC's School of Public Health, analyzed data collected for the Centers for Disease Control and Prevention's 1999-2000 National Health and Nutrition Examination Survey.

The Wangs found that more than half of all adults surveyed (58.2 percent) had blood pressure readings that placed them into the categories of either hypertension or prehypertension, a new, lower-threshold designation set last year in the Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation and Treatment of High Blood Pressure, known as JNC7.

Prehypertension is indicated by systolic/diastolic readings of between 120/80 and 139/89. If either the systolic or diastolic blood pressure falls within this range, it indicates prehypertension. Hypertension remains defined as 140/90 or above in the JNC7 classifications.

The Wangs used data collected from 4,805 adults age 18 or older. They analyzed the group by age, sex, body weight group, ethnicity and socioeconomic status, as determined by education. They also analyzed awareness of hypertension and efforts taken to control it, based on questions asked of survey participants.

The most pronounced prevalence of either prehypertension or hypertension was: among non-Hispanic blacks (63 percent), especially men (69 percent); among all those surveyed age 60 and over (88 percent); among those with less than a high school education (65 percent); and among those with body-mass indexes over 30, which indicates obesity.

"The prevalence of either prehypertension or hypertension among both men and women who were not overweight is 47 percent. But among those overweight, it increases to almost 60 percent, and among those who were obese, their prevalence was 76 percent," said lead author Youfa Wang. "This is of great concern, as recent national survey data show that approximately two-thirds of American adults are overweight or obese."

The Wangs found that awareness and appropriate management of high blood pressure among hypertensive patients remains low. One-third were not aware of their condition, and among those who were aware, only 31 percent had their blood pressure controlled at target levels.

Mexican-Americans had the lowest awareness of their hypertension and were the least likely to manage the condition. Only 58 percent were ever told by their health care providers that they had the condition.

"Socioeconomic status is probably a major factor, which influences access to health care," said Wang. "Mexican-Americans are less likely to see doctors for examinations or treatments than were other population groups."

The Wangs' analysis also found that the prevalence of high blood pressure among all American adults increased considerably during the past decade, from 20 to 27 percent. Earlier data from the 1970s and 1980s, however, showed high blood pressure then was on the decline.

Youfa Wang calls the new findings a "timely wake-up call to the general population of the United States, to physicians and to health care professionals. We need to get people's attention and continue efforts to prevent or control hypertension," he said.

"People need to adopt lifestyle modifications, change their diets, try to be more active and get more exercise, quit smoking," said Wang. "This can all help control blood pressure, reduce the risk of developing hypertension and future risks of cardiovascular disease."

Support for the study came from grants from UIC and the National Institutes of Health.