Results of the study of more than 800 adults were published in the April 23 issue of The Journal of the American Medical Association. Those that were counseled on weight loss, improved exercise and a low-salt diet and who were given specific dietary instructions lowered systolic blood pressure (the upper number) by 11 mmHg and diastolic blood pressure (the lower number) by 6.4 mmHg over a six-month period. The number of people with uncontrolled hypertension dropped from 37 percent to just 12 percent.
Participants lost an average of 13 pounds, improved fitness, reduced salt intake, ate three additional servings of fruit and vegetables each day, increased dietary calcium and lowered the amounts of total fat and saturated fat they ate. The percentage of participants with optimal blood pressure (defined as systolic blood pressure less than 120 mmHg and diastolic blood pressure less than 80 mmHg) increased from 0 to 35. Only a few required blood pressure medications.
"Our study shows that people can simultaneously make multiple lifestyle changes that lower their blood pressure and improve their health," says study chair Lawrence J. Appel, M.D., M.P.H., professor of medicine, epidemiology and international health. "The key issue now is helping people maintain these changes so they don't revert back to less healthy behaviors."
The group that had the best outcomes received counseling on the Dietary Approaches to Stop Hypertension (DASH) diet, which emphasizes fruits, vegetables and low-fat dairy products. It includes whole grains, poultry, fish and nuts, and is reduced in fats, red meat, sweets and sugar-containing beverages. This group also was advised to exercise, lose weight and reduce salt intake.
Appel and colleagues followed 810 adults with elevated blood pressure at four clinical centers: Johns Hopkins; Pennington Biomedical Research Center, Baton Rouge, La.; Duke University Medical Center, Durham, N.C.; and Kaiser Permanente Center for Health Research, Portland, Ore. The average age of participants was 50. Sixty-two percent were women and 34 percent were African-American. Overall, the participants were overweight and sedentary.
PREMIER participants were assigned randomly to one of three groups. The first group had one 30-minute session with a registered dietitian offering general advice on lowering blood pressure. The second group had 18 counseling sessions over the six-month period on losing weight, reducing salt and increasing exercise but no advice on the DASH diet. A third group also had 18 sessions, but the counseling included advice on the DASH diet (as well as the counseling on exercise, weight loss and salt reduction). Those in the groups with 18 counseling sessions kept track of their physical activity and food intake.
While members of all three groups lowered blood pressure, the third group had the best results. Those in this group doubled the reduction in blood pressure compared with those in the group that received one session. The third group also was much less likely to need blood pressure medications. By six months, 19 people in the one-session group needed blood pressure drugs, compared with two people in the second group and five people in the third group.
Appel acknowledges that adopting multiple changes can sometimes be a challenge. "For people who have a hard time with this, start with one change, like exercising, and then add others as you can." Before starting or increasing their exercise, people should check with their physician, he says.
The study was supported by the National Heart, Lung and Blood Institute. Appel chaired the writing group; his co-authors were Catherine M. Champagne, Ph.D.; Lawton S. Cooper, M.D.; Patricia J. Elmer, Ph.D.; David W. Harsha, Ph.D.; Pao-Hwa Lin, Ph.D.; Eva Obarzanek, Ph.D.; Victor J. Stevens, Ph.D.; Laura P. Svetkey, M.D.; William M. Vollmer, Ph.D.; and Deborah R. Young, Ph.D.
PREMEIR Collaborative Research Group, "Effects of Comprehensive Lifestyle Modification on Blood Pressure Control: Main Results of the PREMIER Clinical Trial," The Journal of the American Medical Association, April 23, 2003.
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National Heart, Lung and Blood Institute (NHLBI) http://www.nhlbi.nih.gov
Facts about the DASH diet - from NHLBI http://www.nhlbi.nih.gov/health/public/heart/hbp/dash/index.htm
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