News Author: Laurie Barclay, MD

Adults with prehypertension can maintain changes in lifestyle that reduce progression to hypertension for 18 months, according to the results of a randomized study by Patricia J. Elmer, PhD, and colleagues from the PREMIER Collaborative Research Group, reported in the April 4 issue of the Annals of Internal Medicine.

"This study underscores the value of lifestyle changes — namely improving diet and increasing physical activity — in reducing high blood pressure, an important public health problem," National Heart, Lung and Blood Institute of Health (NHLBI) director Elizabeth G. Nabel, MD, said in a news release. "For the millions of Americans with prehypertension and hypertension, this shows that individuals can make healthy lifestyle changes to keep blood pressure under control without the use of medications."

From January 2000 through November 2002, 810 men and women aged 25 and older with either prehypertension (120 - 139 mm Hg/80 - 89 mm Hg) or stage 1 hypertension (140 - 159 mm Hg/90 - 95 mm Hg) but who were not taking antihypertensive medications were randomized to 3 groups. Two of the groups (established groups) were prescribed goals for weight loss and physical activity and were given sodium and alcohol intake limits, and they received 18 counseling sessions during the first 6 months, including 14 group meetings and 4 individual sessions. During the last 12 months, participants in these 2 groups received 12 group meetings and 3 individual sessions.

One of these groups also received guidance on following the Dietary Approaches to Stop Hypertension diet (DASH), which is high in fruits and vegetables and low-fat dairy products and low in saturated, total fat, and dietary cholesterol. The US Dietary Guidelines for Americans recommend DASH as an example of a healthy eating plan, and previous NHLBI studies have shown that DASH lowers blood pressure.

The third group served as a control. Participants in this group received only two 30-minute counseling sessions regarding standard recommendations for blood pressure control; one at study enrollment and one 6 months later, as well as a third session if desired at the end of the trial after 18-month measurements were completed. Follow-up for blood pressure measurement at 18 months was 94%.

Compared with advice only, both behavioral interventions were associated with statistically significant reductions in weight, fat intake, and sodium intake. The DASH group also had statistically significant increases in fruit, vegetable, dairy, fiber, and mineral intakes.

Compared with the control group, the odds ratios for hypertension at 18 months were 0.83 (95% confidence interval [CI], 0.67 - 1.04) for the established group and 0.77 (95% CI, 0.62 - 0.97) for the established plus DASH group. Reductions in absolute blood pressure at 18 months were greater for participants in the established and the established plus DASH groups than in the control group, but these differences did not reach statistical significance.

"These rates of hypertension control produced by the two interventions are even better than the 50% control rates typically found when single drug therapy is used to control high blood pressure," says study investigator William M. Vollmer, PhD, from Kaiser Permanente Center for Health Research.

Study limitations include limited generalizability because of the exclusion criteria and the volunteer nature of the cohort; and duration was too short and sample size too small to assess intervention effects on clinical cardiovascular events.

"Participants in the two intervention groups made greater changes than those in the control group and saw the greatest benefit in blood pressure status," says coauthor Eva Obarzanek, PhD. "This shows that people at risk for heart disease can successfully and simultaneously make multiple changes in lifestyle, for a substantial benefit."