The Incidence of Metabolic Syndrome in People Over 40 Years Old with Normal Fasting Plasma Glucose and the Predictive Cutoff Value of Effective Fasting Plasma Glucose for Metabolic Syndrome in Guiyang

PURPOSE: This study aimed to investigate the incidence of metabolic syndrome (MS) in people over 40 years of age with normal blood glucose levels in Guiyang’s urban areas and determine the effective glycemic cutoff value for predicting MS. METHODS: The analysis was based on anthropometric and biochemical indicators of residents aged 40 years or older in urban areas of Guiyang City who participated in the “Epidemiological Study of Tumor Risk in Chinese Patients with Type 2 Diabetes” in 2011. This study included 3509 patients (2567 females and 942 males) with normal fasting plasma glucose (FPG) and no MS. Multivariate logistic regression was used to analyze the correlation between FPG and MS ROC was used to analyze the effective cutoff value of FPG for the incidence of MS. RESULTS: After 3-year follow-up, 675 patients had MS (567 females and 108 males). MS incidence in the total population was 19.24%, 11.46% in males, and 22.09% in females, and it increased with FPG. After multivariate logistic regression analysis, the risk of MS corresponding to FPG in females and males was OR=4.607,95% CI (3.477–6.105) and OR=2.944, 95% CI (1.785–4.855), respectively. ROC results demonstrated that FPG could predict the onset of MS (AUC: 0.720 in males and 0.666 in females). CONCLUSION: Increased FPG correlated with the incidence of metabolic syndrome. Subjects with FPG in the normal range still had a high incidence of MS. The population cutoff value for predicting effective FPG for metabolic syndrome was 5.545 mmol/L in men and 5.605 mmol/L in women. Epidemiological investigations are needed to determine whether a lower FPG cutoff value is required to diagnose MS. FPG not only diagnoses diabetes but also serves as a cost-effective and convenient screening method for developing of MS in the general Chinese population.