Dietary carbohydrate quantity and quality and risk of cardiovascular disease, all-cause, cardiovascular and cancer mortality: A systematic review and meta-analysis

Abstract

Background & aims: Evidence remains conflicted on the association between dietary carbohydrate quantity and quality and risk of cardiovascular disease, all-cause, cardiovascular and cancer mortality, and such meta-analyses are lacking. The study aimed to conduct a systematic review and meta-analysis to synthesize the knowledge about their associations and to explore the dose–response relations. Methods: We comprehensively searched PubMed, EMBASE, and Web of Science up to March 2022 for observational studies investigating the associations in adults. Random effect model was used to estimate the summary relative risks (RRs) and 95% confidence intervals (CIs) and the dose−response association was explored by restricted cubic splines. Results: We obtained the data from 41 eligible studies. Compared with participants with lowest dietary carbohydrate intake, those with highest intake had an RR of 1.10 (95% CI 1.03–1.17, I² = 52.8%) for cardiovascular disease, 1.10 (0.98–1.24, I² = 65.5%) for coronary heart disease (CHD), 1.20 (1.08–1.34, I² = 0) for stroke, 1.07 (1.00–1.14, I² = 61.9%) for all-cause mortality, 1.02 (0.92–1.14, I² = 51.3%) for cardiovascular mortality, and 1.01 (0.89–1.13, I² = 56.7%) for cancer mortality. For each 5 %E increase in dietary carbohydrate intake, the summary RR was 1.02 (1.00–1.04, I² = 66.8%) for cardiovascular disease, 1.04 (1.01–1.06, I² = 0) for stroke but not significant for other outcomes. Restricted cubic splines showed linear associations with risk of cardiovascular disease (P<inf>non-linearity</inf> = 0.143), CHD (P<inf>non-linearity</inf> = 0.508), stroke (P<inf>non-linearity</inf> = 0.654) and non-linear associations with all-cause mortality (P<inf>non-linearity</inf> = 0.008) and cardiovascular mortality (P<inf>non-linearity</inf> = 0.055). Limited studies were found on the association of cardiovascular disease and mortality with dietary carbohydrate quality using a multidimensional and integrated indicator. Conclusions: Increased consumption of dietary carbohydrate intake is associated with increased risk of cardiovascular disease, stroke, and all-cause mortality. Linear relation was found for cardiovascular disease and stroke but non-linear relation for all-cause mortality. More studies are warranted to investigate the association of dietary carbohydrate quality using a combined indicator and cardiovascular disease and mortality.