title: Subclinical hypothyroidism is associated with higher carotid intima-media thickness in cross-sectional analysis of the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil).
abstract: Although subclinical hypothyroidism (SCH) is associated with cardiovascular risk, there is scarce data about subclinical atherosclerosis in subjects with SCH. We aimed to analyze the association between SCH and carotid intima-media thickness (IMT) using baseline data from the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil).
  
  
  
  We included subjects with normal thyroid function (TSH: 0.4-4.0 mIU/l, and normal free thyroxine (FT4): 0.8-1.9 ng/dl) and SCH (TSH ≥ 4.0 mIU/l and normal FT4) evaluated for IMT in a cross-sectional analysis. We excluded individuals using medications that affect thyroid function and those with a history of cardiovascular disease. We performed logistic and linear regression models to evaluate the association with IMT (mean values and categorized at the 75th percentile) as a dependent variable and SCH as an independent variable, adjusted for other cardiovascular risk factors. From 8623 subjects (median age of 50 years; interquartile range: 44-57), 4624 (53.6%) were women, 8095 (93.9%) were euthyroid, and 528 (6.1%) had SCH. Groups varied in age, body mass index, Framingham risk score, Homeostasis Model Assessment for Insulin Resistance (HOMA-IR), C-reactive protein, as well as, IMT, that were all higher in SCH compared to euthyroid participants. SCH is associated with IMT as a continuous variable (β = 0.010, P = 0.036) and IMT >75th percentile: OR = 1.30 (95% CI = 1.06-1.59) in logistic models.
  
  
  
  Individuals with SCH presented higher IMT compared with euthyroid subjects, even after adjustment for potential confounders. IMT was independently associated with SCH in the baseline of the ELSA-Brasil study.
authors.affiliation: Centro de Pesquisa Clínica e Epidemiológica, Hospital Universitário, Universidade de São Paulo, São Paulo, Brazil.
authors.forename: É J F
authors.initials: ÉJ
authors.lastname: Peixoto de Miranda
authors.affiliation: Centro de Pesquisa Clínica e Epidemiológica, Hospital Universitário, Universidade de São Paulo, São Paulo, Brazil.
authors.forename: M S
authors.initials: MS
authors.lastname: Bittencourt
authors.affiliation: Laboratório de Genética, Instituto do Coração, Av. Dr. Enéas de Carvalho Aguiar, 4 Bloco 2, 10° andar, ZIP: 05403-000 São Paulo, SP, Brazil.
authors.forename: A C
authors.initials: AC
authors.lastname: Pereira
authors.affiliation: Centro de Pesquisa Clínica e Epidemiológica, Hospital Universitário, Universidade de São Paulo, São Paulo, Brazil.
authors.forename: A C
authors.initials: AC
authors.lastname: Goulart
authors.affiliation: Centro de Pesquisa Clínica e Epidemiológica, Hospital Universitário, Universidade de São Paulo, São Paulo, Brazil.
authors.forename: I S
authors.initials: IS
authors.lastname: Santos
authors.affiliation: Centro de Pesquisa Clínica e Epidemiológica, Hospital Universitário, Universidade de São Paulo, São Paulo, Brazil.
authors.forename: P A
authors.initials: PA
authors.lastname: Lotufo
authors.affiliation: Centro de Pesquisa Clínica e Epidemiológica, Hospital Universitário, Universidade de São Paulo, São Paulo, Brazil. Electronic address: isabensenor@gmail.com.
authors.forename: I M
authors.initials: IM
authors.lastname: Bensenor
mesh_terms: D000328:Adult; D000368:Aged; D058070:Asymptomatic Diseases; D015415:Biomarkers / Q000097:blood; D001938:Brazil; D002340:Carotid Artery Diseases / Q000000981:diagnostic imaging* / Q000209:etiology*; D059168:Carotid Intima-Media Thickness; D016009:Chi-Square Distribution; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007037:Hypothyroidism / Q000097:blood / Q000150:complications* / Q000175:diagnosis; D016014:Linear Models; D016015:Logistic Models; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D016017:Odds Ratio; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012307:Risk Factors; D013960:Thyroid Function Tests; D013963:Thyroid Hormones / Q000097:blood
chemical_list: D015415:Biomarkers; D013963:Thyroid Hormones
keywords: Cardiovascular risk factors; Carotid intima-media thickness; Subclinical atherosclerosis; Subclinical hypothyroidism; Thyroid dysfunction