Dietary patterns and cardiovascular mortality in the Melbourne Collaborative Cohort Study.

BACKGROUND: Despite increased cardiovascular disease risk factors, migrants to Australia from Mediterranean countries have lower mortality than do native-born Australians. Dietary patterns may contribute to this.

OBJECTIVE: The objective was to investigate the relation between dietary patterns and mortality from cardiovascular (CVD) and ischemic heart disease (IHD) in an ethnically diverse population.

DESIGN: This was a prospective cohort study (mean follow-up: 10.4 y) of 40 653 volunteers (23 980 women) aged 40-69 y in the Melbourne Collaborative Cohort Study (1990-1994); 24% of the subjects were Mediterranean born.

RESULTS: Four dietary factors were identified from a food-frequency questionnaire with the use of principal components analysis. They explained 69% of intake variance and reflected frequent intakes of Mediterranean foods, vegetables, meat, and fresh fruit. The Mediterranean factor was inversely associated with CVD and IHD mortality in models adjusting for diabetes, waist-to-hip ratio, body mass index, and hypertension. For IHD, the hazard ratio (HR) for the highest compared with the lowest quartile of consumption was 0.59 (95% CI: 0.39, 0.89; P for trend = 0.03). Associations persisted in analyses excluding people with prior CVD (HR: 0.51; 95% CI: 0.30, 0.88; P for trend = 0.03). Vegetable and fresh fruit factors were inversely associated with CVD mortality but only among those without prior CVD. HRs (highest compared with lowest quartile) were 0.66 (95% CI: 0.48, 0.92; P for trend = 0.02) for vegetables and 0.69 (95% CI: 0.52, 0.93; P for trend = 0.04) for fresh fruit. The meat factor was not associated with CVD or IHD mortality.

CONCLUSION: Our findings suggest that frequent consumption of traditional Mediterranean foods is associated with reduced cardiovascular mortality after controlling for important risk factors and country of birth.