Life Extension Magazine

Life Extension Magazine May 2005

Abstracts

Hypertension

Effect of antihypertensive agents on cardiovascular events in patients with coronary disease and normal blood pressure: the CAMELOT study: a randomized controlled trial.

CONTEXT: The effect of antihypertensive drugs on cardiovascular events in patients with coronary artery disease (CAD) and normal blood pressure remains uncertain. OBJECTIVE: To compare the effects of amlodipine or enalapril vs placebo on cardiovascular events in patients with CAD. DESIGN, SETTING, AND PARTICIPANTS: Double-blind, randomized, multicenter, 24-month trial (enrollment April 1999-April 2002) comparing amlodipine or enalapril with placebo in 1991 patients with angiographically documented CAD (>20% stenosis by coronary angiography) and diastolic blood pressure <100 mm Hg. A substudy of 274 patients measured atherosclerosis progression by intravascular ultrasound (IVUS). INTERVENTIONS: Patients were randomized to receive amlodipine, 10 mg; enalapril, 20 mg; or placebo. IVUS was performed at baseline and study completion. MAIN OUTCOME MEASURES: The primary efficacy parameter was incidence of cardiovascular events for amlodipine vs placebo. Other outcomes included comparisons of amlodipine vs enalapril and enalapril vs placebo. Events included cardiovascular death, nonfatal myocardial infarction, resuscitated cardiac arrest, coronary revascularization, hospitalization for angina pectoris, hospitalization for congestive heart failure, fatal or nonfatal stroke or transient ischemic attack, and new diagnosis of peripheral vascular disease. The IVUS end point was change in percent atheroma volume. RESULTS: Baseline blood pressure averaged 129/78 mm Hg for all patients; it increased by 0.7/0.6 mm Hg in the placebo group and decreased by 4.8/2.5 mm Hg and 4.9/2.4 mm Hg in the amlodipine and enalapril groups, respectively (P<.001 for both vs placebo). Cardiovascular events occurred in 151 (23.1%) placebo-treated patients, in 110 (16.6%) amlodipine-treated patients (hazard ratio [HR], 0.69; 95% CI, 0.54-0.88 [P = .003]), and in 136 (20.2%) enalapril-treated patients (HR, 0.85; 95% CI, 0.67-1.07 [P = .16]. Primary end point comparison for enalapril vs amlodipine was not significant (HR, 0.81; 95% CI, 0.63-1.04 [P = .10]). The IVUS substudy showed a trend toward less progression of atherosclerosis in the amlodipine group vs placebo (P = .12), with significantly less progression in the subgroup with systolic blood pressures greater than the mean (P = .02). Compared with baseline, IVUS showed progression in the placebo group (P<.001), a trend toward progression in the enalapril group (P = .08), and no progression in the amlodipine group (P = .31). For the amlodipine group, correlation between blood pressure reduction and progression was r = 0.19, P = .07. CONCLUSIONS: Administration of amlodipine to patients with CAD and normal blood pressure resulted in reduced adverse cardiovascular events. Directionally similar, but smaller and nonsignificant, treatment effects were observed with enalapril. For amlodipine, IVUS showed evidence of slowing of atherosclerosis progression.

JAMA. 2004 Nov 10;292(18):2217-25

Prevalence of the metabolic syndrome among US adults: findings from the third National Health and Nutrition Examination Survey.

CONTEXT: The Third Report

of the National Cholesterol Education Program Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (ATP III) highlights the importance of treating patients with the metabolic syndrome to prevent cardiovascular disease. Limited information is available about the prevalence of the metabolic syndrome in the United States, however. OBJECTIVE: To estimate the prevalence of the metabolic syndrome in the United States as defined by the ATP III report. DESIGN, SETTING, AND PARTICIPANTS: Analysis of data on 8814 men and women aged 20 years or older from the Third National Health and Nutrition Examination Survey (1988-1994), a cross-sectional health survey of a nationally representative sample of the noninstitutionalized civilian US population. MAIN OUTCOME MEASURES: Prevalence of the metabolic syndrome as defined by ATP III (>/=3 of the following abnormalities): waist circumference greater than 102 cm in men and 88 cm in women; serum triglycerides level of at least 150 mg/dL (1.69 mmol/L); high-density lipoprotein cholesterol level of less than 40 mg/dL (1.04 mmol/L) in men and 50 mg/dL (1.29 mmol/L) in women; blood pressure of at least 130/85 mm Hg; or serum glucose level of at least 110 mg/dL (6.1 mmol/L). RESULTS: The unadjusted and age-adjusted prevalences of the metabolic syndrome were 21.8% and 23.7%, respectively. The prevalence increased from 6.7% among participants aged 20 through 29 years to 43.5% and 42.0% for participants aged 60 through 69 years and aged at least 70 years, respectively. Mexican Americans had the highest age-adjusted prevalence of the metabolic syndrome (31.9%). The age-adjusted prevalence was similar for men (24.0%) and women (23.4%). However, among African Americans, women had about a 57% higher prevalence than men did and among Mexican Americans, women had about a 26% higher prevalence than men did. Using 2000 census data, about 47 million US residents have the metabolic syndrome. CONCLUSIONS: These results from a representative sample of US adults show that the metabolic syndrome is highly prevalent. The large numbers of US residents with the metabolic syndrome may have important implications for the health care sector.

JAMA. 2002 Jan 16;287(3):356-9

The effects of low-carbohydrate versus conventional weight loss diets in severely obese adults: one-year follow-up of a randomized trial.

BACKGROUND: A previous paper reported the 6-month comparison of weight loss and metabolic changes in obese adults randomly assigned to either a low-carbohydrate diet or a conventional weight loss diet. OBJECTIVE: To review the 1-year outcomes between these diets. DESIGN: Randomized trial. SETTING: Philadelphia Veterans Affairs Medical Center. PARTICIPANTS: 132 obese adults with a body mass index of 35 kg/m2 or greater; 83% had diabetes or the metabolic syndrome. INTERVENTION: Participants received counseling to either restrict carbohydrate intake to <30 g per day (low-carbohydrate diet) or to restrict caloric intake by 500 calories per day with <30% of calories from fat (conventional diet). MEASUREMENTS: Changes in weight, lipid levels, glycemic control, and insulin sensitivity. RESULTS: By 1 year, mean (+/-SD) weight change for persons on the low-carbohydrate diet was -5.1 +/- 8.7 kg compared with -3.1 +/- 8.4 kg for persons on the conventional diet. Differences between groups were not significant (-1.9 kg [95% CI, -4.9 to 1.0 kg]; P = 0.20). For persons on the low-carbohydrate diet, triglyceride levels decreased more (P = 0.044) and high-density lipoprotein cholesterol levels decreased less (P = 0.025). As seen in the small group of persons with diabetes (n = 54) and after adjustment for covariates, hemoglobin A1c levels improved more for persons on the low-carbohydrate diet. These more favorable metabolic responses to a low-carbohydrate diet remained significant after adjustment for weight loss differences. Changes in other lipids or insulin sensitivity did not differ between groups. LIMITATIONS: These findings are limited by a high dropout rate (34%) and by suboptimal dietary adherence of the enrolled persons. CONCLUSION: Participants on a low-carbohydrate diet had more favorable overall outcomes at 1 year than did those on a conventional diet. Weight loss was similar between groups, but effects on atherogenic dyslipidemia and glycemic control were still more favorable with a low-carbohydrate diet after adjustment for differences in weight loss.

Ann Intern Med. 2004 May 18;140(10):778-85

Blocking carbohydrate absorption and weight loss: a clinical trial using Phase 2 brand proprietary fractionated white bean extract.

Background: Phase 2’ starch neutralizer brand bean extract product (“Phase 2”) is a water-extract of a common white bean (Phaseolus vulgaris) that has been shown in vitro to inhibit the digestive enzyme alpha-amylase. Inhibiting this enzyme may prevent the digestion of complex carbohydrates, thus decreasing the number of carbohydrate calories absorbed and potentially promoting weight loss. Methods: Fifty obese adults were screened to participate in a randomized, double-blind, placebo-controlled study evaluating the effects of treatment with Phase 2 versus placebo on weight loss. Participants were randomized to receive either 1500 mg Phase 2 or an identical placebo twice daily with meals. The active study period was eight weeks. Thirty-nine subjects completed the initial screening process and 27 subjects completed the study. Results: The results after eight weeks demonstrated the Phase 2 group lost an average of 3.79 lbs (average of 0.47 lb per week) compared with the placebo group, which lost an average of 1.65 lbs (average of 0.21 lb per week), representing a difference of 129 percent (p=0.35). Triglyceride levels in the Phase 2 group were reduced an average of 26.3 mg/dL, more than three times greater a reduction than observed in the placebo group (8.2 mg/dL) (p=0.07). No adverse events during the study were attributed to the study medication. Conclusion: Clinical trends were identified for weight loss and a decrease in triglycerides, although statistical significance was not reached. Phase 2 shows potential promise as an adjunct therapy in the treatment of obesity and hypertriglyceridemia and further studies with larger numbers of subjects are warranted to conclusively demonstrate effectiveness.

Altern Med Rev. 2004 Mar;9(1):63-9

Effect of DHEA on abdominal fat and insulin action in elderly women and men: a randomized controlled trial.

CONTEXT: Dehydroepiandros-terone (DHEA) administration has been shown to reduce accumulation of abdominal visceral fat and protect against insulin resistance in laboratory animals, but it is not known whether DHEA decreases abdominal obesity in humans. DHEA is widely available as a dietary supplement without a prescription. OBJECTIVE: To determine whether DHEA replacement therapy decreases abdominal fat and improves insulin action in elderly persons. DESIGN AND SETTING: Randomized, double-blind, placebo-controlled trial conducted in a US university-based research center from June 2001 to February 2004. PARTICIPANTS: Fifty-six elderly persons (28 women and 28 men aged 71 [range, 65-78] years) with age-related decrease in DHEA level. INTERVENTION: Participants were randomly assigned to receive 50 mg/d of DHEA or matching placebo for 6 months. MAIN OUTCOME MEASURES: The primary outcome measures were 6-month change in visceral and subcutaneous abdominal fat measured by magnetic resonance imaging and glucose and insulin responses to an oral glucose tolerance test (OGTT). RESULTS: Of the 56 men and women enrolled, 52 underwent follow-up evaluations. Compliance with the intervention was 97% in the DHEA group and 95% in the placebo group. Based on intention-to-treat analyses, DHEA therapy compared with placebo induced significant decreases in visceral fat area (-13 cm2 vs +3 cm2, respectively; P = .001) and subcutaneous fat (-13 cm2 vs +2 cm2, P = .003). The insulin area under the curve (AUC) during the OGTT was significantly reduced after 6 months of DHEA therapy compared with placebo (-1119 muU/mL per 2 hours vs +818 muU/mL per 2 hours, P = .007). Despite the lower insulin levels, the glucose AUC was unchanged, resulting in a significant increase in an insulin sensitivity index in response to DHEA compared with placebo (+1.4 vs -0.7, P = .005). CONCLUSION: DHEA replacement could play a role in prevention and treatment of the metabolic syndrome associated with abdominal obesity.

JAMA. 2004 Nov 10;292(18):2243-8

The natural treatment of hypertension.

The goal of this review is to evaluate the efficacy of commonly available dietary supplements in the treatment of hypertension, using the average blood pressure reduction achieved with the implementation of lifestyle modifications as a standard. For this reason, the authors focus on the antihypertensive potential of these agents rather than pharmacology, pharmacokinetics, adverse effects, or supplement-drug interactions. For the purpose of this review, dietary supplements are defined as exhibiting some evidence of benefit if a systolic blood pressure reduction of 9.0 mm Hg or greater and/or a diastolic blood pressure reduction of 5.0 mm Hg or greater has been observed in previously published, peer-reviewed trials. These defining limits are based on the average blood pressure reduction associated with the implementation of certain lifestyle modifications. Agents with some evidence of benefit include coenzyme Q10, fish oil, garlic, vitamin C, and L-arginine.

J Clin Hypertens (Greenwich). 2004 May;6(5):242-8