Periodic feedback to reduce cholesterol levels

Abstract

The effectiveness of biweekly feedback regarding blood total cholesterol (TCH) to assist dietary adherence and lower blood TCH levels was assessed in a mixed population of healthy and cardiac diseased subjects (S) engaging in an unsupervised mall walking program. Based upon screening with a portable lipid analyzer (and with their physician's permission) 36 S’s (x age=63, 83% females) with TCH levels between 200-300 mg/dl were randomized to control (CG) or experimental groups (EG). The CG received instruction regarding the National Cholesterol Education Program's Step 1 low-fat, low-cholesterol diet at 0, 2, 4, 6 weeks and completed 3-day food records at 0, 4, 8 weeks. In addition to this instruction, the EG received graphic feedback regarding their TCH at 0, 2, 4, and 6 weeks. Both groups had a goal of a 10% reduction in TCH. By 8 weeks, the CG increased TCH by 2.2 mg/dl (1%) from 240.2 ± 24.8 to 242.4 ± 40.0 mg/dl while the EG decreased TCH by 11.8 mg/dl (5%) from 239.9 ± 22.6 to 228.1 ± 26.8 mg/dl. Repeated measures ANOVA showed a trend toward a lowering of TCH in the EG (time*group) [FC1,34)=3.39, p=.07]. A one-way repeated measures ANOVA for TCH within the EG between 0 and 8 weeks was significant [F(4,64)=3.14, p=.02]. Goal attainment was statistically greater in the experimental group [z=2.12: p=.0017]). Food record two-way ANOVAS revealed no significant differences between groups over time on dietary intake of fats or dietary cholesterol. Using one-way ANOVAs the experimental group demonstrated a significant pattern of initial decreases from food record 1 to food record 2 which Was maintained at food record 3. A recently reported study conducted in a structured cardiovascular exercise program (Burkett, Southard, Herbert, & Walberg, 1990) showed statistical significance over a 16 week trial period using this feedback technique. The results of the present study suggest that the findings of Burkett, et al. may be generalizable to populations participating in an unsupervised mall walking program.