December 13, 2005
High Cholesterol May Also Raise Blood Pressure
By Maggie Fox, Health and Science Correspondent
WASHINGTON -- People with high cholesterol also have a greater risk of high blood pressure, U.S. researchers reported on Monday in one of the first studies to demonstrate that one may cause the other.A study of 3,000 men monitored for 14 years showed that those who developed the unhealthiest cholesterol levels raised their risk of hypertension by 39 percent.
"There appears to be a significant association between increased cholesterol levels and the risk of developing hypertension in healthy, middle-aged men," said Howard Sesso, an epidemiologist at Brigham and Women's Hospital and Harvard Medical School in Boston.
"We looked at this same exact question in a study published a month ago ... in women. We found the same thing," Sesso said in a telephone interview.
While both conditions lead to heart disease, the No. 1 killer of Americans and people in many other developed nations, Sesso said few researchers had looked at whether high cholesterol could actually cause high blood pressure.
He believes that the damage cholesterol causes to the walls of arteries makes them less elastic, leading to high blood pressure. "Our findings suggest we may have a new means of preventing hypertension, a devastating public heath issue in this country," he said.
As many as 90 percent of U.S. adults with normal blood pressure at age 55 may develop hypertension in their lifetime, according to the American Heart Association.
Unhealthy blood cholesterol is trickier to calculate as it involves several different readings -- high total cholesterol, high levels of low density lipoprotein or "bad" cholesterol and low levels of high density lipoprotein or "good" cholesterol.
But the American Heart Association says nearly 107 million American adults have total blood cholesterol values of more than 200, considered the highest desirable level.
SIMILAR RISK FACTORS
The risk factors for high blood pressure and high cholesterol are similar -- a diet rich in fat, low in whole grains, fruits and vegetables and a lack of exercise.
Sesso's team started with more than 3,000 men taking part in a larger study called the Physician's Health Study. At the beginning all had healthy blood pressure and cholesterol levels.
Over the average of 14 years of follow-up, a third of the men developed high blood pressure, the researchers reported in the latest issue of the journal Hypertension.
Men with the worst levels of bad cholesterol had a 54 percent higher risk of high blood pressure compared to the mean with the healthiest levels.
Men with the highest levels of total cholesterol were 23 percent more likely to develop hypertension than men with the lowest levels. But men with the highest HDL or "good" cholesterol levels had a 32 percent lower risk of high blood pressure than those with the lowest HDL levels.
A second study, published in the journal Circulation, showed total cholesterol levels have decreased in middle-aged to older adults but are rising among younger adults.
A survey of 5,000 adults in Minnesota, ongoing for 20 years, showed that drugs may be responsible.
"The older age groups use more lipid-lowering drugs. This may be partially responsible for the continued reduction of their total cholesterol," said Donna Arnett of the University of Alabama at Birmingham, who led the study.