Public release date: 13-Oct-2008
Study highlights: • An analysis of data from two natonal health studies shows that more U.S. adults have hypertension than ever before. • The percent of those aware of, being treated for and having the disorder under control has increased and as a result more people are living with rather than dying from hypertension. • Researchers say the nation’s obesity epidemic is a major factor for the increase in hypertension prevalence.
DALLAS, Oct. 14, 2008 — First, the bad news: More American adults have hypertension (high blood pressure) and prehypertension than ever before.
Now, the good news: The percentage of those getting treated for and controlling high blood pressure has also increased. As a result, even the bad news has a good news aspect: more people are living with rather than dying from hypertension.
The bad news–good news portrait of the disease — reported in Hypertension: Journal of the American Heart Association — emerged from an analysis of data from two national health studies. Researchers at the National Heart, Lung, and Blood Institute (NHLBI), of the National Institutes of Health, said the nation’s obesity epidemic is a major factor in the increased prevalence of hypertension.
“That confirms what others have observed based on more limited data and what one would expect, because obesity is an important cause of high blood pressure,” said Jeffrey A. Cutler, M.D., lead author of the study and a consultant to NHLBI’s Divisions of Prevention and Population Sciences and Cardiovascular Diseases.
Researchers compared the hypertension findings of the third National Health and Nutrition Examination Survey (NHANES III), which ran from 1988–1994, with data from the first six years (1999–2004) of the current NHANES, which collects information continuously in two-year blocks. They examined data from 16,351 NHANES III respondents and 14,430 surveyed during 1999–2004, all age 18 or older.
The age-standardized prevalence rate for hypertension rose from 24.4 percent to 28.9 percent. Being overweight or obese accounted for part but not all of the increase in high blood pressure among different age and race/ethnicity groups.
Prevalence is an estimate of the total number of cases of a disease existing in a population during a specified period. Prevalence is often expressed as a percentage of the population.
“We see that much of the magnitude in men is accounted for by obesity, but less so in women, possibly because of some unexplored changes in risk factors for hypertension,” said Paul D. Sorlie, Ph.D., co-author of the study and Epidemiology Branch Chief in the Division of Prevention and Population Sciences.
The most notable change in most race and gender groups was an upward trend in blood pressure categories. This lowered the percent of Americans with normal pressure (from 55.5 percent to 50.3 percent). Prehypertension — defined as readings of 120 to less than 140 systolic and/or 80 to 89 diastolic — increased from 32.3 percent to 36.1 percent. (Systolic is the upper number—the pressure when the heart is beating, while diastolic, the lower number, is the pressure when the heart is relaxing.)