Nearly one in five young U.S. adults may have high blood pressure, researchers said on Wednesday in a study suggesting the problem of hypertension is more widespread than previously thought.
Hypertension is easy to prevent and inexpensive to treat through diet, exercise and drugs, yet it is the second-leading cause of death in the United States. The Institute of Medicine, part of the National Academy of Sciences that often conducts studies for the government, last year declared high blood pressure a "neglected disease" that costs the U.S. health system $73 billion a year.
The latest findings by a team at the University of North Carolina at Chapel Hill are in sharp contrast to a federal government study by the National Health and Nutrition Examination Survey that suggested only 4 percent of young adults might have high blood pressure, a condition that raises the risk of strokes and heart attacks.
Both studies used the same definition of hypertension: a blood pressure reading of 140 over 90 millimeters of mercury or more. Normal blood pressure is considered to be 120 over 80 or lower.
"The findings are significant because they indicate that many young adults are at risk of developing heart disease, but are unaware that they have hypertension," said Quynh Nguyen, a doctoral student at the University of North Carolina at Chapel Hill, whose study appears online in the journal Epidemiology.
The researchers did not study why the numbers may be rising or relate the findings to U.S. intake of sodium, a major contributor to high blood pressure.
U.S. health officials say the study is a worrisome signal, but are cautious to embrace the new findings until they have been confirmed in other studies.
High blood pressure, or too much force exerted by blood as it moves against vessel walls, is the leading risk factor for premature death worldwide.
For the study, the team analyzed data on more than 14,000 men and women between 24 and 32 years old in 2008 from the National Longitudinal Study of Adolescent Health, known as Add Health, funded by the National Institutes of Health.
They found 19 percent had elevated blood pressure, and only about half of these individuals had ever been told by their doctor that they had the condition.
The team considered several explanations for the discrepancy between the two studies, including differences in the participants, where they were examined, and the accuracy and reliability of the measured blood pressures.
None could account for the gap in the hypertension estimates between the two surveys.
"What we have is a new observation and we need to examine why did the numbers come out this way," Dr. Steven Hirschfeld of the National Institute of Child Health and Human Development, one of the National Institutes of Health, said in a telephone interview.
"This one study by itself shouldn't lead us to a revision of health policy or health assessment. it is just a signal we need to examine in greater detail," he said.
Kathleen Mullan Harris of the University of North Carolina at Chapel Hill who led the study said the findings may differ, but the message is clear.
"Young adults and the medical professionals they visit shouldn't assume they're not old enough to have high blood pressure. This is a condition that leads to chronic illness, premature death and costly medical treatment," Harris said in a statement.