ABSTRACT: BACKGROUND: Few studies have investigated the specific effect of single intervention components in randomized controlled trials. The purpose was to investigate the effect of adding group-based diet and exercise counseling to individual life-style counseling on long-term changes in dietary habits. METHODS: The study was a randomized controlled intervention study. From a general Danish population, aged 30 to 60 years (n=61,301), two random sample were drawn (group A, n=11,708; group B, n=1,308). Subjects were invited for a health screening program. Participation rate was 52.5%. All participants received individual life-style counseling. Individuals at high risk of ischemic heart disease in group A were furthermore offered group-based life-style counseling whereas high risk individuals in group B were referred to their general practitioner. The intervention was repeated for high-risk individuals after one and three years. At five-year follow-up all participants were invited for a health examination. High risk individuals were included in this study (n=2 356) and changes in dietary intake were analyzed using multilevel linear regression analyses. RESULTS: At five-year follow-up group A had significantly increased the unsaturated/saturated fat ratio compared to group B (net change at five-year follow-up: 0.09; P=0.01). The fish intake increased significantly in group A compared to group B from baseline to five-year follow-up (net change: 5.4 g/day; P=0.05). The intake of fibre and vegetables increased in both groups, however, no significant difference was found between the groups. In men a significantly greater decrease in saturated fat intake was found in group A compared to group B at 1 year follow-up (net change: -1.13 E%; P=0.003) and a non-significant tendency of a greater decrease in group A was found at five year follow-up (net change: -0.68 E%; P=0.10). No differences were found for saturated fat intake in women between groups. Overall, the results showed an equal effect in group A and B at three years follow-up whereas at five years follow-up a tendency of better maintenance in group A were found. CONCLUSIONS: Offering group-based counseling in addition to individual counseling resulted in small, but significantly improved dietary habits at five-year follow-up and better maintenance, compared to individual counseling alone. Trial registration: The Inter99 study was approved by the local Ethics Committee (KA 98 155) and is registered with ClinicalTrials.gov (registration number: NCT00289237).
Toft, U., Kristoffersen, L., Ladelund, S., Ovesen, L., Lau, C., Pisinger, C., … Jørgensen, T. (2008). The effect of adding group-based counselling to individual lifestyle counselling on changes in dietary intake. The Inter99 study - A randomized controlled trial. International Journal of Behavioral Nutrition and Physical Activity, 5. https://doi.org/10.1186/1479-5868-5-59