Socioeconomic inequalities in the association between diet quality and incident cardiovascular diseases: A prospective study in the Netherlands

AIMS: Lower socioeconomic position (SEP) groups have higher risks of cardiovascular diseases (CVD), with diet quality being a crucial risk factor. However, whether the association between diet quality and incident CVD differs across SEP (education and income) groups is unclear, which was examined in this study. METHODS: This study included participants aged 30-80 years, free of CVD at baseline, from the Dutch Lifelines cohort. The Lifelines Diet Score, a diet quality indicator based on Dutch dietary guidelines, was calculated with data assessed by a 110-item food frequency questionnaire. Cox proportional hazards models were used to assess the association between diet quality and incident CVD (the first non-fatal major cardiovascular event), and whether this association was modified by SEP, adjusted for age, sex, energy intake, alcohol intake, smoking, TV watching time, moderate-to-vigorous physical activity, sleep duration, social/hobby clubs participation, chronic stress, family history of CVD, and BMI. RESULTS: Of 82,360 participants included, 2827 incident CVD cases were identified (median follow-up 7.4 years, incidence rate 4.7 per 1000 person-years). Education modified the association between diet quality and incident CVD (P-interaction = 0.033). Comparing the poorest to the best diet quality quartiles, hazard ratios (95%CI) were 1.27 (1.06, 1.51) in low, 1.28 (1.06, 1.54) in middle, and 0.98 (0.76, 1.27) in high education group. CONCLUSIONS: For low- and middle-education groups, poor diet quality was associated with disproportionately higher risks of incident CVD. Improving diet quality may therefore have the potential to be a core entry point for lowering CVD health inequalities. To address persistent health inequalities, health policies should tackle broader environmental, social, and structural factors of diet and health equity.