Excessive weight is the strongest risk factor for high blood pressure. Recent studies have evaluated different ways to treat and prevent hypertension. Most of these studies evaluated weight loss alone or in combination with antihypertensive medications and showed a reduction in blood pressure. Although losing weight has been shown to reduce blood pressure in patients who are borderline hypertensive, this benefit diminished over time in some studies.

Obesity is difficult to treat, and a significant number of patients who lose weight return to their original weight. In addition, weight loss goals set for overweight persons may be too high or unrealistic. The long-term benefits of modest weight loss, sustained or nonsustained, have not been well studied. Moore and associates studied the effect of the amount of weight lost and the persistence of weight loss on the risk of hypertension in overweight adults.

The study included surviving members of the Framingham Study. These patients were interviewed and examined every two years for eight years. Hypertension was defined as a mean blood pressure of 140/90 mm Hg or higher in two separate readings or as already on antihypertensive medications. In addition to blood pressure measurements, researchers collected data on age, sex, height, body mass index (BMI), education level, alcohol intake, cigarette smoking, and physical activity. Participants were divided into four groups based on weight lost over the first four years. Group 1: stable, weight changed by less than 3 lb 15 oz (1.8 kg). Group 2: 3 lb 15 oz to 7 lb 11 oz (1.8 to 3.5 kg). Group 3: 7 lb 14 oz to 14 lb 12 oz (3.6 kg to 6.7 kg). Group 4: 14 lb 15 oz (6.8 kg) or more. Over the next four years, participants were classified into two groups: those who sustained weight loss and those who did not. Overweight was defined as having a BMI of 25 kg per m2 or higher.

Six hundred and twenty-three overweight middle-age adults (30 to 49 years of age) and 605 overweight older adults (50 to 65 years of age) were included in the study. After adjusting for outside variables, participants who lost 14 lb 15 oz or more during the initial phase of the study had a 21 to 29 percent reduction in the long-term risk of hypertension. When adjusting for cancer and cardiovascular disease, middle-age participants who lost 14 lb 15 oz or more had a 28 percent reduction in long-term hypertensive risk. The older group had a 37 percent reduction. Sustained weight loss in overweight, middle-age adults resulted in seven fewer cases of hypertension per 1,000 person-years compared with those who had a stable weight. Overweight older adults had 13.3 fewer cases of hypertension per 1,000 person-years. Middle-age adults who sustained their weight loss of 3 lb 15 oz or more had a 22 percent reduction in long-term risk of hypertension, and the older group had a 26 percent reduction in risk. When accounting for other comorbidities, the older group had a 36 percent reduction in long-term risk of hypertension.

The authors conclude that even modest weight loss can reduce the long-term risk of developing hypertension. This is particularly true in individuals who maintain the weight loss. The prevention or delay in the onset of hypertension also may decrease the risk of cardiovascular complications associated with hypertension.