Diet, lifestyle, and nonstatin trials: review of time to benefit

How rapidly benefits accrue from nonstatin, lipid-lowering therapies is a 21st-century question posed to data collected in the 20th century. The 3 early dietary trials conducted in institutional settings where diet was strictly controlled demonstrate that, compared with a control diet, cholesterol-lowering diets reduce coronary event rates over several years. These data do not reveal whether a more homogeneous high-risk population would demonstrate an earlier time to benefit. Dietary counseling trials of men with coronary disease conducted in the 1950s and 1960s failed to demonstrate a consistent benefit from dietary therapy, in part because of confounding factors from methodologic flaws in trial design. By the 1980s and 1990s, improvements in trial design, such as larger numbers of subjects, control of confounding risk factors, and limiting trial end points to those directly attributable to atherosclerotic events, were in place. Subsequently, 5 randomized clinical trials showed a consistent benefit of dietary therapy, with significant reductions by 1 to 2 years in fatal events, nonfatal events, and total mortality; 2 of these studies, each including omega-3 fatty acids as part of the dietary intervention, reported a rapid and significant time to benefit (within 3 to 6 months). Additional lifestyle benefits of cardiac rehabilitation (a surrogate for physical activity) and smoking cessation clearly show long-term benefit at 1 and 5 years, respectively. Nonstatin drug and surgical therapies either have shown no significant benefit (estrogen, dextrothyroxine) or benefit after 1 to 5 years of therapy (intestinal bypass surgery, cholestyramine, clofibrate, niacin, and a combination of niacin and clofibrate). In conclusion, rapid time to benefit has been observed in older lifestyle and nonstatin trials that have included omega-3 fatty acids as a component of dietary therapy. Lifestyle changes in diet, physical activity, weight loss, and smoking cessation remain important and effective therapies with which significant long-term benefits can be expected.