Long-Term Weight Loss And Changes In Blood Pressure - Brief Article

Nutrition Research Newsletter, Feb, 2001

With hypertension affecting approximately one quarter of the U.S. adult population, prevention and treatment of this deadly disease is a necessity. Pharmacologic treatment for hypertension significantly decreases morbidity and mortality from cardiovascular diseases. However, it can have undesirable side effects, be expensive, and is often not initiated when blood pressure is below diagnostic thresholds for hypertension. On the other hand, weight loss has been shown to reduce blood pressure in overweight patients regardless of the level of hypertension they have.

The Trials of Hypertension Prevention (TOHP) Phase I showed that a mean weight reduction of 3.9 kg at 18 months in overweight subjects with high-normal blood pressure resulted in significant decreases of systolic and diastolic blood pressure. To investigate whether non-pharmacologic interventions can prevent hypertension over the long term, TOHP II was initiated.

Subjects of TOHP II were overweight adults (110-165% of their IBW), aged 30-54, with non-medicated diastolic blood pressure of 83-89 mm Hg and systolic blood pressure less than 140 mm Hg. All subjects were randomly assigned to one of four groups: weight loss only, sodium reduction only, combined weight loss and sodium reduction, or a control group. Baseline blood pressure and weights were taken and then measured every 6 months to the end of follow-up at 36, 42, or 48 months, depending on randomization date. Participants assigned to the weight-loss groups sought to lose at least 4.5 kg (10 lb) during the first six months of the interventions and to maintain their weight loss for the remainder of the study. This intervention was a three-year program of group meetings and individual counseling, focused on dietary change, physical activity, and social support.

Mean weight loss from baseline in the intervention groups was 4.4 kg at 6 months, 2.0 kg at 18 months, and 0.2 kg at 36 months. Mean weight change in the control group (n=596) at the same time points was 0.1, 0.7, and 1.8 kg. Men had a greater net weight loss than women, and white persons lost more weight than black persons. At all follow-up points, the weight loss and control groups differed significantly in both diastolic and systolic blood pressure. As expected, subjects who lost the most weight showed the largest reductions in blood pressure. Subjects who lost at least 4.5 kg at six months and maintained this loss for the next 30 months had the greatest reduction in blood pressure and a relative risk for hypertension of 0.35. No differences in response of blood pressure to weight loss were seen according to ethnicity.

As seen in other trials, a direct dose-response relationship was observed between weight loss and blood pressure reduction. However, TOHP II showed significant long-term reductions in blood pressure and reduced risk of hypertension can be achieved with even modest weight loss. The problem is that only 13% of the intervention participants were able to lose 4.5 kg or more and maintain this weight over three years. Therefore, the challenge is to develop weight-loss programs that achieve higher long-term success rates.

Victor J. Stevens, Eva Obarzanek, Nancy R. Cook, et al., Long-Term Weight Loss and Changes in Blood Pressure: Results of the Trials of Hypertension Prevention, Phase II, Annals of Internal Medicine 134:1-11 (January 2, 2001) [Reprints: Victor J. Stevens, PhD, Kaiser Permanente Center for Health Research, 3800 North Interstate Ave., Portland, OR 97227. E-mail: victor.j.stevens@kpchr.org].