title: Thyrotropin Levels, Insulin Resistance, and Metabolic Syndrome: A Cross-Sectional Analysis in the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil).
abstract: BACKGROUND
  Previous studies have described an association with thyrotropin (TSH) levels, insulin resistance, and metabolic syndrome. We performed a cross-sectional analysis to investigate the relationship between TSH levels, insulin resistance, and metabolic syndrome using baseline data from the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil).
  
  
  METHODS
  Diabetics and individuals using medications that interfere in thyroid function were excluded, leaving 10,935 participants (54.3% women) for current analyses. Homeostasis Model Assessment of Insulin Resistance (HOMA-IR) values above the 75th percentile was considered as indicative of presence of insulin resistance. Logistic regression models were built using HOMA-IR and metabolic syndrome as the dependent variable, and quintiles of TSH as the independent variable (first quintile as reference). Odds ratios (OR) were presented with multivariate adjustment for socioeconomic/cardiovascular risk factors for insulin resistance, and adjustment only for socioeconomic factors and smoking for metabolic syndrome.
  
  
  RESULTS
  Age, body mass index, waist measurement, fasting glucose and fasting and post load insulin and HOMA-IR increased according to TSH quintiles. Subjects in the fifth TSH quintile presented an OR of association with insulin resistance of 1.86 [95% confidence interval (95% CI) 1.26-2.75], regardless of gender. For the metabolic syndrome, subjects in the fifth quintile presented an OR of 1.21 (95% CI 1.01-1.45) and remained positive only for men (OR 1.37; 95% CI 1.07-1.76). Restricting the analysis to quintiles of TSH in the normal range did not change the results.
  
  
  CONCLUSIONS
  In this cross-sectional evaluation, high TSH quintiles were associated to insulin resistance/metabolic syndrome.
authors.affiliation: 1 Center for Clinical and Epidemiological Research, Hospital Universitário, University of São Paulo , São Paulo, Brazil .
authors.forename: Isabela M
authors.initials: IM
authors.lastname: Benseñor
authors.affiliation: 1 Center for Clinical and Epidemiological Research, Hospital Universitário, University of São Paulo , São Paulo, Brazil .
authors.forename: Alessandra Carvalho
authors.initials: AC
authors.lastname: Goulart
authors.affiliation: 2 Federal University of Espírito Santo , Vitória, Espírito Santo, Brazil .
authors.forename: Maria del Carmen B
authors.initials: Mdel C
authors.lastname: Molina
authors.affiliation: 1 Center for Clinical and Epidemiological Research, Hospital Universitário, University of São Paulo , São Paulo, Brazil .
authors.forename: Érique José Peixoto
authors.initials: ÉJ
authors.lastname: de Miranda
authors.affiliation: 1 Center for Clinical and Epidemiological Research, Hospital Universitário, University of São Paulo , São Paulo, Brazil .
authors.forename: Itamar S
authors.initials: IS
authors.lastname: Santos
authors.affiliation: 1 Center for Clinical and Epidemiological Research, Hospital Universitário, University of São Paulo , São Paulo, Brazil .
authors.forename: Paulo A
authors.initials: PA
authors.lastname: Lotufo
mesh_terms: D000328:Adult; D000368:Aged; D001938:Brazil / Q000453:epidemiology; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007333:Insulin Resistance; D008137:Longitudinal Studies; D008297:Male; D024821:Metabolic Syndrome / Q000097:blood / Q000453:epidemiology* / Q000378:metabolism*; D008875:Middle Aged; D013960:Thyroid Function Tests; D013972:Thyrotropin / Q000097:blood*
chemical_list: D013972:Thyrotropin