By Steven ReinbergHealthDay Reporter

TUESDAY, Jan. 27, 2015 (HealthDay News) — Young and middle-aged adults with high systolic blood pressure — the top number in the blood pressure reading — may have an increased risk for heart disease, a new study suggests.

“High blood pressure becomes increasingly common with age. However, it does occur in younger adults, and we are seeing early onset more often recently as a result of the obesity epidemic,” said study senior author Dr. Donald Lloyd-Jones. He is a professor of epidemiology and cardiology at Northwestern University Feinberg School of Medicine in Chicago.

Earlier, small studies have suggested that isolated systolic high blood pressure might be harmless in younger adults, or the result of temporary nervousness at the doctor’s office, Lloyd-Jones said.

But this 30-year study suggests — but does not prove — that isolated systolic high blood pressure in young adulthood (average age 34) is a predictor of dying from heart problems 30 years down the road.

“Doctors should not ignore isolated systolic high blood pressure in younger adults, since it clearly has implications for their future health,” Lloyd-Jones said.

For the study, Lloyd-Jones and colleagues followed more than 27,000 adults, ages 18 to 49, enrolled in the Chicago Heart Association Detection Project in Industry Study.

Women with high systolic pressure were found to have a 55 percent higher risk of dying from heart disease than women with normal blood pressure. For men, the difference was 23 percent.

The readings to watch for: systolic pressure of 140 mm Hg or more and diastolic pressure (the bottom number) of less than 90 mm Hg. Normal blood pressure is less than 120 mm Hg over 80 mm Hg, the American Heart Association says.

Systolic pressure measures the force of blood moving through arteries when the heart beats, or contracts, while diastolic pressure is the pressure in the arteries between heartbeats, according to the heart association.

The percentage of U.S. adults under 40 with isolated systolic high blood pressure more than doubled between 1994 and 2004, raising concerns about the potential health consequences, the researchers say.

The report was published Jan. 26 online in the Journal of the American College of Cardiology.

Dr. Michael Weber, a professor of medicine at the State University of New York Downstate College of Medicine in New York City, welcomed the study.

“We now can have confidence that even moderately high blood pressure in young people does carry risk and should be treated,” he said.

“Treating young people may give us a good opportunity to make lifelong changes that could protect them from heart disease and strokes in later life,” he said. Such treatment might include lifestyle changes and medications to lower blood pressure, he added.

Weber, author of an editorial accompanying the study, said systolic pressure is a predictor of who is likely to develop heart disease, have a stroke or suffer kidney damage.

Although it hasn’t been proven, he’s a strong believer that controlling blood pressure in young adulthood will prevent heart disease later in life.

“We believe that if you control your blood pressure now, many years from now you will be grateful you did this because you will have improved your heart health immeasurably,” he said.

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SOURCES: Donald Lloyd-Jones, M.D., professor, epidemiology and cardiology, Northwestern University Feinberg School of Medicine, Chicago; Michael Weber, M.D. professor, medicine, division of cardiovascular medicine, State University of New York Downstate College of Medicine, Brooklyn, N.Y.; Jan. 26, 2015, Journal of the American College of Cardiology, online