BackgroundStudies suggest an association between a high TSH and (individual components of) the metabolic syndrome. Only a few studies have been performed in the general older population.ObjectiveThis study investigates the association between serum TSH and the metabolic syndrome in a representative sample of older persons in The Netherlands.Design and patientsData of the Longitudinal Aging Study Amsterdam were used, which is an ongoing cohort study in a representative sample of Dutch older persons. A total of 1187 subjects (590 men and 597 women) between the ages of 65 and 88 years participated in the study.MeasurementsMetabolic syndrome (US National Cholesterol Education Program definition) and its individual components were assessed, as well as serum TSH levels.ResultsAmong the participants, the prevalence of the metabolic syndrome was 34.2%. The mean serum TSH was 1.9 mU/l. Subjects in the upper quartile with a serum TSH level above 2.28 mU/l (odds ratio (OR)=1.68; 95% confidence interval (CI) 1.19–2.37) had a significantly increased prevalence of metabolic syndrome compared with subjects in the lowest quartile with a serum TSH below 1.04 mU/l. After adjustment for confounders, age, sex, alcohol use, total physical activity, and smoking, the OR was 1.62 (95% CI 1.15–2.32).ConclusionsSubjects with a serum TSH in the upper quartile have a higher prevalence of metabolic syndrome as compared with subjects with a serum TSH in the lowest quartile.