Daily Rice Intake Strongly Influences the Incidence of Metabolic Syndrome in Japanese Men Aged 40–59 Years

Objectives: The first objective of this study was to classify men aged 40–74 yrs with metabolic syndrome (MetS) according to daily rice intake, and the second was to investigate physical measurements, physiological examinations, blood biochemical assays, intake of food other than rice and lifestyle and environmental factors in the study group. Methods: We analyzed data from 6095 men aged 40–74 yrs who had undergone full medical examinations. The men were classified into 3 age groups: (1) 40–49 yrs, (2) 50–59 yrs, and (3) 60–74 yrs. The men were classified further into 3 groups according to daily rice intake: group 1 (≤300 g), group 2 (300–450 g), and group 3 (≥450 g). The relationship between daily rice intake and the following factors was analyzed in the three age brackets: (1) physical measurements including waist circumference, (2) physiological measurements, (3) serum biochemical indices, (4) whether or not the person was taking medication for hypertension, diabetes mellitus or serum lipid abnormalities, (5) lifestyle, and (6) consumption of foods other than rice. Results: Daily rice intake was related strongly to the occurrence of MetS in all three age brackets. Multiple logistic regression analysis showed (1) a significant increase in the odds ratio for MetS (1.461 times) for group 3 compared with group 1 in men aged 40–49 yrs and (2) a significant increase in the odds ratio for MetS (1.501 times) for group 3 compared with group 1 in men aged 50–59 yrs. However, there was no significant difference in the odds ratio for MetS among rice intake groups in the 60–74 age bracket. Conclusion: In men aged 40–59 yrs, daily rice intake strongly influenced the incidence of MetS, whereas in men aged 60–74 yrs, there was no relationship between daily rice intake and MetS.