The National Heart, Lung, and Blood Institute (NHLBI) advocates dietary changes as the primary way of lowering one's cholesterol level, at least in people who aren't at high risk for coronary heart disease. Unfortunately, studies have shown that it's hard to get patients to change their eating habits enough to improve their lipid profile. In an attempt to address this, researchers from the University of Pittsburgh (Pennsylvania) School of Nursing and the Graduate School of Public Health designed a randomized, controlled trial to study the effects of an educational intervention, based on "self-efficacy theory," on adherence to dietary goals and low-density-lipoprotein cholesterol (LDL-C) levels.

Self-efficacy is the idea that one will perform or achieve in accordance with how one believes he will. Two primary components of the theory are "efficacy expectancy" (the extent to which one believes she can change behavior-in this case, one's eating) and "outcome expectancy" (the extent to which one believes such changes will benefit-in this case, whether changing diet will lower the cholesterol level and improve health).

Of 121 subjects deemed eligible for the study, only 65 consented to participate and were randomized into the two study groups. Most patients were white (94%), and more than half were male. All participants were considered "nonadherent" in following a cholesterol-lowering diet.

Every two weeks, the study intervention group received six telephone calls designed to help subjects adhere to dietary recommendations. The control group received usual care consisting of follow-up visits to the clinician and the measurement of lipid levels every three to six months.

The diet-adherence rate was higher and LDL-C levels were lower in the intervention group (LDL-C was reduced by 6% versus a 1.3% increase in the usual care group). Oddly, despite these favorable outcomes, self-efficacy and outcome expectancy scores were not significantly different from those in the control group. The authors surmise that "a longer period of dietary success is required before self-efficacy changes," and that the three-month intervention period "was too brief to detect a difference in perceived efficacy," and they conclude that these interventions "may be sufficient to delay or prevent the use of lipid-lowering drugs."-Doug Brandt

Burke LE, et al. Patient Educ Couns 2005; 57(1):134-42.