People with prehypertension and hypertension can make and sustain multiple lifestyle modifications, controlling their blood pressure and perhaps reducing their risk for many chronic diseases, according to Patricia J. Elmer, Ph.D., of Kaiser Permanente Northwest's center for health research, Portland, Ore., and her associates.
They reported the results at 18-month follow-up of a randomized, multicenter study of middle-aged people. The study, funded by the National Heart, Lung, and Blood Institute, enrolled 810 subjects across the country with a systolic blood pressure of 120–159 mm Hg and a diastolic blood pressure of 80–95 mm Hg.
Almost all participants were overweight or obese, 62% were women, and 34% were African American.
One subject group (268 people) received a behavioral intervention including advice to lose at least 15 pounds, perform at least 180 minutes per week of moderate-intensity physical activity, consume no more than 100 mmol per day of sodium, and drink no more than 1–2 alcoholic drinks per day.
A second group (269 subjects) received the same behavioral intervention plus additional advice to follow the DASH (Dietary Approaches to Stop Hypertension) diet, increasing their consumption of fruits, vegetables, and low-fat dairy products and decreasing their intake of total fat and saturated fat.
Both intervention groups kept food diaries, monitored their calorie and sodium intakes, and recorded minutes of physical activity.
In both groups, the subjects attended 14 group and 4 individual counseling sessions for the first 6 months, then attended monthly group sessions supplemented with 3 individual counseling sessions for the following 12 months. At these sessions, counseling focused on self-monitoring, reinforcement, and problem-solving, and it also promoted social support and individual motivation.
The third group of study subjects (273 people) received only advice rather than a behavioral intervention. They attended a 30-minute individual session at enrollment in the study and another 6 months later, at which they were counseled to lose weight, reduce sodium intake, increase physical activity, and eat a heart-healthy diet.
At 18 months, the prevalence of mild hypertension had decreased in all three groups, from a high of 36%–38% at baseline to 32% in the advice-only group to 24% in the behavioral intervention group instructed in established, guideline-recommended lifestyle changes; and to 22% in the behavioral intervention group instructed in those changes plus the DASH diet. This result compares favorably with the degree of blood pressure control reported for drug therapy in community-based studies, the investigators said (Ann. Intern. Med. 2006;144:485–95).
None of the subjects had normal blood pressure at baseline, but at 18 months the rates of normal blood pressure were 18%, 24%, and 24% in these three groups, respectively.
Fitness, as measured by heart rate on treadmill testing, improved in all three groups. Subjects in all groups also lost weight, but the mean weight loss was significantly greater in the two behavioral intervention groups than in the advice-only group. Subjects in both intervention groups reduced their intake of sodium and fat; those in the DASH diet group also significantly increased their intake of fruits, vegetables, dairy products, and important nutrients such as fiber, folate, and minerals—all of which “may reduce the risk for chronic disease,” Dr. Elmer and her associates said.
Adherence to these lifestyle modifications decreased between 6 and 18 months, with “recidivism” in weight loss, sodium intake, and potassium intake. However, subjects in the two intervention groups still maintained about a 4% weight loss at 18 months. This “modest” reduction “should be viewed in the context of public health goals that emphasize the prevention of additional weight gain, rather than weight loss, because of the well-documented difficulties of sustaining weight loss,” the researchers said.
They noted that randomized controlled trials typically recruit highly motivated volunteers, so the results of this trial may not be generalizable to the overall population.