BACKGROUND:Metabolic syndrome comprises a cluster of metabolic abnormalities leading to insulin resistance and atherosclerosis, and Helicobacter pylori is thought to be a contributing factor.AIM:We examined the association between H. pylori infection and metabolic syndrome in a large Japanese population.METHOD:Consecutive asymptomatic subjects that underwent a complete medical survey in our institute between April 2006 and March 2007 were recruited, and a total of 5,488 men and 1,906 women were cross-sectionally studied. The association of H. pylori serostatus with traditional atherosclerosis risk factors was investigated by multiple linear regression analysis. Independent and significant factors affecting metabolic syndrome were determined by multiple logistic regression analysis.RESULTS:H. pylori seropositivity significantly increased with age in both men and women. H. pylori seropositivity was significantly higher in cases with metabolic syndrome compared with those without metabolic syndrome (P < 0.001). There was a significant and independent association between H. pylori seropositivity and metabolic syndrome (OR 1.39, 95% CI 1.18–1.62, P < 0.001) by multiple logistic regression analysis. H. pylori seropositivity was significantly associated with higher systolic blood pressure (β coefficient = 1.03, P = 0.014), lower high-density lipoprotein (HDL)-cholesterol level (β coefficient = −2.00, P < 0.001), and higher LDL-cholesterol level (β coefficient = 2.21, P = 0.005) by multiple linear regression analysis.CONCLUSION:In a large Japanese population, H. pylori infection was significantly associated with metabolic syndrome.