Effects of the Quebec Heart Health Demonstration Project on adult dietary behaviours

Background. There are few studies which have evaluated the dietary impact of multiple community-based cardiovascular disease prevention programs. Methods. A 5-year, multifactorial community-based heart disease prevention program was conducted by regional public health departments in three sites: urban, suburban and rural. The experimental and control communities were composed of independent samples of 4,863 adults in 1993 and 5,260 in 1997. The impact of the program on diet was assessed by a validated, self-administered food frequency questionnaire which yielded a Global Dietary Index (GDI). Results. The urban and suburban sites showed improvements in mean GDI in both exposed and non-exposed groups while the rural site mean GDI showed deterioration in both groups (n.s.). The analysis of variance showed that the group × year interaction terms were not significant for each site and sex, indicating that the intervention did not have measurable effects on dietary behaviours. Inclusion of confounding variables did not alter those findings. Analyses of specific food group indices gave similar results. Conclusions. Future intervention programs could benefit from considering physical and social environments as well as public policy changes to improve efficacy.