Grain Subtype and the Combination of Grains Consumed Are Associated with the Risk of Metabolic Syndrome: Analysis of a Community-Based Prospective Cohort

Abstract

Background: Evidence on the prospective association between grain consumption and metabolic syndrome (MetS) is lacking. Objective: This study explored the association between grain intake by subtype or various combinations of grain intake and the risk of developing MetS in South Korean adults using data from a community-based prospective cohort study. Methods: A total of 5717 participants (2984 men and 2733 women) aged 40-69 y without MetS were followed up for 10 y (2001-2012). Grain consumption was assessed using a semiquantitative FFQ at baseline (2001-2002) and a follow-up examination (2005-2006). A multivariate Cox proportional hazards model was used to examine the risk of incident MetS and its components according to grain consumption (<1, 1 to <3, or ≥3 servings/d) by sex. Results: In total, 2218 participants (38.8%) developed MetS. Frequent consumers of whole grains (≥3 servings/d) had a lower risk of incident MetS (men - HR: 0.51; 95% CI: 0.41, 0.63; P = 0.0001; women - HR: 0.73; 95% CI: 0.60, 0.90; P = 0.0029), whereas frequent consumers of refined grains had a higher risk of incident MetS (men - HR: 1.63; 95% CI: 1.31, 2.03; P < 0.0001; women - HR: 2.25; 95% CI: 1.82, 2.78; P < 0.0001) compared with rare consumers (<1 serving/d). The combination of low whole grains (<2 servings/d) and high refined grains (≥2 servings/d) was associated with a higher risk of MetS than the combination of high whole grains and low refined grains (men - HR: 1.21; 95% CI: 1.04, 1.41; P = 0.012; women - HR: 1.43; 95% CI: 1.23, 1.66; P < 0.0001). Conclusions: Higher consumption of whole grains was associated with lower risk of incident MetS, whereas higher refined-grain consumption was associated with a higher risk in a middle-aged and older Korean population.