High cholesterol may lead to high blood pressure in men

Men with high total cholesterol are much more likely to develop high blood pressure than men with low total cholesterol, according to a study in Hypertension: Journal of the American Heart Association.

Hypertension, defined as blood pressure at or higher than 140/90 millimeters of mercury (mm Hg), is the most common chronic disease in the United States. As many as 90 percent of U.S. adults with normal blood pressure at age 55 may develop hypertension in their lifetime, said Howard D. Sesso, Sc.D., M.P.H., author of the study.

"Hypertension and lipids are both related to the risk of cardiovascular disease," said Sesso, associate epidemiologist at Brigham and Women's Hospital and assistant professor of medicine at Harvard Medical School in Boston. "We took one step backwards to try to understand whether adverse lipid levels might predate the development of hypertension in men."

Researchers analyzed data from the Physicians' Health Study, an ongoing clinical trial that collected baseline blood samples of 3,110 men (average age 48) free from hypertension, cardiovascular disease and cancer at the start of the study. Over an average of 14 years follow-up, about a third (1,019) developed hypertension.

The researchers measured total cholesterol and high-density lipoprotein (HDL) - "good" cholesterol - then calculated non-HDL cholesterol (defined as total cholesterol minus HDL cholesterol) and the ratio of total cholesterol to HDL cholesterol.

"It appears that lipids do have a role in the development of hypertension," Sesso said. "We found a positive association between higher levels of total cholesterol, non-HDL cholesterol and total cholesterol-to-HDL cholesterol ratio and an increased risk of hypertension. Those men who had higher levels of HDL cholesterol had a significantly lower risk for developing hypertension than men who had the low levels of HDL cholesterol."

The researchers divided study participants into five groups, or quintiles, from the lowest levels to the highest for each lipid category. They found that men in the:

• highest fifth of total cholesterol were 23 percent more likely to develop hypertension than men in the lowest quintile for total cholesterol;
  
• highest quintile of non-HDL cholesterol were 39 percent more likely than those in the lowest quintile to develop hypertension;
  
• highest quintile for total cholesterol-to-HDL cholesterol ratio were at a 54 percent increased risk for hypertension compared with those in the lowest quintile in that category.
  

They also found that men in the highest quintile for HDL levels had a 32 percent lower risk of developing hypertension than those in the lowest quintile.