Cardiovascular disease risk and dietary fibre intake in the United Kingdom Women's Cohort Study

Background: Dietary fibre has been associated with risk of cardiovascular disease (CVD) in some cohort studies around the world. Key health messages may be created by examining the types or sources of fibre in the diet and associated risk of different CVD events but few studies have explored this. Methods: I conducted a systematic literature review of published studies investigating dietary fibre intake and CVD. Associations were explored using dose-response meta-analysis in addition to potential non-linear associations. CVD event data for the UK Women’s Cohort Study were obtained from death records, hospital episode statistics (HES) and the Myocardial Ischaemia National Audit Project (MINAP). Capture-recapture methods were then applied to estimate the potential for missing cases. Survival analyses for coronary heart disease (CHD), stroke and total CVD risk in association with total fibre intake and fibre from key food sources were conducted using a cohort approach for food frequency data and case-cohort methods were used for analyses with food diary data. Results: Meta-analyses broadly supported inverse associations between CVD and fibre intake. Combined data from 9 studies indicate lower CVD risk per 7g/day greater intake in total fibre, relative risk 0.91 (95% confidence intervals (CI) 0.88, 0.94). After 14 years, 821 CHD and 388 stroke cases were observed. Total fibre, soluble, insoluble and fibre from cereals assessed using FFQs were associated with lower risk of stroke. With each 6g/day higher total fibre intake, hazard ratio (HR) 0.89 (95% CI: 0.81, 0.99). Higher fibre density was associated with lower risk of myocardial infarction, for every 2g/1000kcal/day higher intake, HR 0.89 (95% CI: 0.81, 0.98). Higher cereal fibre intake, calculated using food diaries, was associated with lower risk of acute coronary events HR 0.76 (95% CI: 0.58, 1.00). Conclusion: Fibre intake is inversely associated with CVD risk in a dose response relationship after accounting for other potentially confounding influences. Associations were stronger for stroke risk, when the source of fibre was cereals and in those without hypertension.