Longitudinal association of dietary carbohydrate and the risk cardiovascular disease: a dose-response meta-analysis

Previous findings on the association of dietary carbohydrate with cardiovascular disease (CVD) events and mortality are inconsistent. We aimed to assess the relationship between dietary carbohydrate and the incidence of cardiovascular events and mortality. A comprehensive literature search of MEDLINE (PubMed), Scopus, ISI Web of Science, and EMBASE, was performed up to June 2019. Prospective cohort studies which examined dietary carbohydrate in relation to fatal and non-fatal myocardial infarction, fatal and non-fatal stroke, heart failure, and sudden cardiac death were included in our study. Summary HRs and 95% CIs were estimated using a random-effects model. A total of 19 cohort studies including 15,663,111 participants were identified. Combining 27 effect sizes with 1,577,225 CVD cases led to a significant association between dietary carbohydrate and total CVD events (HR= 1.05, 95% CI: 1.00, 1.10; I² = 38.5%), but no association was observed between dietary carbohydrate and CVD mortality (HR = 1.02; 95% CI: 0.91, 1.14; I²=27.1%, derived from 8 effect sizes with 106,412 events), and CHD events (HR = 1.03, 95% CI: 0.98, 1.09; I² = 46.6%, derived from 18 effect sizes with 1,549,281 events). Moreover, using 8 effect sizes with 6,829 cases, higher carbohydrate intake was associated with increased risk of stroke (HR = 1.13; 95% CI: 1.01, 1.27; I²= 0.0%). In subgroup analysis by sex, higher carbohydrate intake increased the risk of total CVD events (HR: 1.10; 95% CI: 1.03, 1.17; I² = 0.0%), and CHD (HR: 1.10; 95% CI: 1.01, 1.20; I²= 15.0%), but not stroke and CVD mortality in women. No significant association was found in men. Low- to very-low-certainty evidence suggests that higher carbohydrate intake is directly but slightly associated with CVD and stroke risk, while no association was found for CHD and CVD mortality. We also found sex-specific associations.