Inverse Association Between Iodine Status and Prevalence of Metabolic Syndrome: A Cross-Sectional Population-Based Study in a Chinese Moderate Iodine Intake Area

PURPOSE: To investigate the relationship between iodine intake status and the prevalence of metabolic syndrome (MetS) through a population-based survey. PATIENTS AND METHODS: In total, 2691 Chinese adults participated in this cross-sectional study, and they were stratified by urinary iodine concentration (UIC) and sex. Fasting blood samples were used to assess biochemical parameters, including thyroid function and antibodies. Urine samples were collected in the morning to measure UIC. Multivariate regression logistic analysis was performed for the overall population and sex subgroups. RESULTS: An inverse association was observed between iodine intake status and MetS prevalence in Chinese adults. Compared with individuals with adequate iodine status, those with high-iodine status had significantly low MetS risks, and the adjusted odds ratios (95% confidence interval) were 0.70 (0.57–0.86, P <0.01) and 0.75 (0.6–0.95, P <0.05). A high MetS risk was observed in the iodine-deficient group, which did not reach statistical significance. There was a significant inverse linear trend between the risk of MetS and UIC in the total population and male subgroup (P for trend <0.05), which was not observed in the female subgroup (P for trend >0.05). CONCLUSION: An inverse association was observed between iodine intake status and the risk of developing MetS in Chinese adults. Sufficient iodine status is a potential protective factor for MetS development. Males may benefit from increased iodine intake, while females would need to achieve a more-than-adequate iodine status to gain metabolic benefits.