Adherence to the Dutch dietary guidelines is inversely associated with 20-year mortality in a large prospective cohort study

BACKGROUND/OBJECTIVES: The Dutch guidelines for a healthy diet aim to reduce major chronic diseases. However, supporting evidence on their overall association with all-cause and cause-specific mortality is limited. Recently, the Dutch Healthy Diet-index (DHD-index) has been developed to assess adherence to these guidelines. The aim was to examine the association between the DHD-index and all-cause mortality and deaths from cardiovascular disease (CVD), coronary heart disease (CHD), stroke and cancer. SUBJECTS/METHODS: We followed 3593 men and women aged 55 years and older enrolled in the Rotterdam Study, a populationbased prospective cohort study, from baseline in 1990–1993 to 2011. A validated 170-item food frequency questionnaire at baseline was used to calculate the DHD-index score (maximum 90 points). Cox proportional hazard models were used to estimate hazard ratios (HRs) adjusting for age, sex, total energy intake, smoking and educational level. RESULTS: During the 20-year follow-up, 1831 (51%) deaths were reported. Mean DHD-index score was 60.6 (s.d. 10.6). The score was inversely associated with all-cause mortality (highest vs lowest quartile HR 0.77; 95% confidence interval (CI) 0.67, 0.89). Inverse but non-significant associations were observed for mortality due to CVD (HR 0.74; 95% CI 0.55, 1.01), CHD (HR 0.60; 95% CI 0.34, 1.06) and stroke (HR 0.67; 95% CI 0.36, 1.22), whereas no association was observed with cancer mortality (HR 0.99; 95% CI 0.90, 1.11). CONCLUSIONS: A higher level of adherence to the Dutch dietary guidelines, as assessed with the DHD-index, was associated with a lower risk of all-cause mortality, probably due to an inverse association with cardiovascular causes of death.