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NHLBI Study Finds Simultaneous Lifestyle Changes Effectively Lowers Blood Pressure
Results of the study, called PREMIER, appear in the April 23, 2003 issue of The Journal of the American Medical Association.
"This is the first time a host of behavioral steps to prevent or control high blood pressure has been put together in one intervention," said NHLBI Director Dr. Claude Lenfant. "Past studies looked at one or two changes at a time, and it was thought that doing more would prove too hard. But PREMIER shows that an all-in-one approach works and can help Americans reduce their blood pressure, lowering their risk for heart disease and stroke."
"PREMIER underscores the importance of lifestyle changes as a first-line weapon in the fight against high blood pressure," said Dr. Lawrence J. Appel, Professor of Medicine at The Johns Hopkins Medical Institutions in Baltimore, MD, and a coauthor of the article. "Those in the study who made the greatest lifestyle changes had the best blood pressure results. Millions of Americans can benefit by using these lifestyle changes to control high blood pressure — or prevent it in the first place."
High blood pressure is a major risk factor for heart disease and the chief risk factor for stroke. Even blood pressure slightly above normal increases the risk.
About 50 million American adults — one in four — have hypertension and the risk of developing it increases with age.
Recommended lifestyle steps to prevent or control hypertension are to: lose weight if overweight, follow a heart-healthy eating plan, which includes reducing salt and other forms of sodium, increase physical activity, limit consumption of alcoholic beverages, and quit smoking. Additionally, results of earlier studies, published in December 2001 and April 1997, showed that the DASH diet significantly lowers blood pressure, especially when combined with reduced sodium intake. DASH stands for "Dietary Approaches to Stop Hypertension."
PREMIER dealt with all of the hypertension prevention and control steps. The study began in 1998 and was conducted at four clinical centers. It included 810 participants with blood pressures of 120-159 mm Hg systolic and 80-95 mm Hg diastolic. (Higher-than-optimal blood pressure is 120-139/80-89 mm Hg; stage 1 hypertension is 140-159/90-99 mm Hg.) At the start of the trial, 38 percent of participants had hypertension, and most were overweight and sedentary. Sixty-two percent were women and 34 percent were African American.
Participants were randomly assigned to one of three groups: Advice-Only, Established, and Established Plus DASH. All three groups received printed materials about blood pressure and lifestyle. In addition, those in the Advice-Only group received a 30-minute individual session with a nutritionist, which did not include counseling on how to make behavior changes. Those in the Established group had 18 counseling sessions in 6 months — 14 group meetings and 4 individual sessions. They kept track of their diet, including calorie and sodium consumption, and their physical activity. Those in the Established Plus DASH group had the same intervention schedule as those in the Established group, but also were taught to follow the DASH diet and to record their daily servings of fruits, vegetables, dairy products, and fat.
After 6 months, blood pressure levels had declined in all three groups but the reduction was significantly more in the two intervention groups and most in the Established Plus DASH group. Systolic blood pressure decreased on average by 11.1 mm Hg in the Established Plus DASH group, 10.5 mm Hg in the Established group, and 6.6 in the Advice-Only group; diastolic blood pressure decreased on average by 6.4 mm Hg in the Established Plus DASH group, 5.5 mm Hg in the Established group, and 3.8 in the Advice-Only group.
The percent of those with hypertension dropped after 6 months from 37 to 12 in the Established Plus DASH group, from 37 to 17 in the Established group, and from 38 to 26 in the Advice-Only group.
After 6 months, the percent of those able to control their high blood pressure also was greatest in the Established Plus DASH group. Seventy-seven percent of hypertensives in that group lowered their blood pressure to under 140/90 — by comparison, drug treatment typically controls blood pressure in about 50 percent of those with stage 1 hypertension, according to the article. About 66 percent of hypertensives in the Established group and 48 percent of hypertensives in the Advice-Only group brought their hypertension under control.
Other key results include:
Optimal blood pressure (less than 120 mm Hg systolic and less than 80 mm Hg diastolic) was achieved in 35 percent of the Established Plus DASH group, 30 percent of the Established group, and 19 percent of the Advice-Only group.
Fewer of those in the two intervention groups who started the trial without high blood pressure went on to develop hypertension — 6 percent in the Established Plus DASH group, 8 percent in the Established group, and 11 percent in the Advice-Only group.
Consumption of fruits, vegetables, and dairy products significantly increased in the Established Plus DASH group, compared to the other two groups. A third of those in the Established Plus DASH group consumed nine or more servings of fruits and vegetables daily, compared with only 6 percent of those in the other groups. Fifty-nine percent of those in the Established Plus DASH group consumed two or more dairy servings a day, compared with about 34 percent of the Advice-Only and about 28 percent of the Established groups.
Significant weight loss occurred in all groups — the average losses for those who were overweight at the start of the study were about 13 pounds in the Established Plus DASH group, about 11 pounds in the Established group, and about 3 pounds in the Advice-Only group.
"One of the key findings in PREMIER is that people can not only follow the DASH diet on their own but also can lose weight on it, even though it calls for many more servings of fruits and vegetables a day than Americans typically consume," said Dr. Eva Obarzanek, NHLBI nutritionist and PREMIER Project Officer. "The new findings mean that it's feasible for Americans to use the eating plan, lose weight if they're overweight, and protect themselves against the risks of high blood pressure."