title: Relationship of thyroid-stimulating hormone levels to development of dyslipidemia and determination of an ideal cut-off point to start replacement therapy.
abstract: OBJECTIVE
  There are studies showing a strong association between thyroid dysfunction and increased cardiovascular risk due to lipid profile changes. The purpose of this study was to assess the degree of association and predictive power of thyroid-stimulating hormone (TSH) levels in relation to lipid profile changes, identifying the TSH cut-off point beyond which lipid changes occur.
  
  
  METHODS
  A cross-sectional, retrospective study in Quito (Ecuador) conducted from January 2004 to December 2008 on patients first attending the endocrinology department.
  
  
  RESULTS
  A total of 278 histories were analyzed, and a 36.3% prevalence of subclinical hypothyroidism was found. No association was found between sex and cholesterol or between sex and low density lipoprotein (LDL). However, associations were found between sex and dyslipidemia, sex and body mass index (BMI), and sex and TSH. Linear regression analysis between LDL and TSH, cholesterol and TSH, and BMI and TSH showed significant associations in all cases, with Pearson R2 coefficients of 0.80, 0.81, and 0.85 respectively.
  
  
  CONCLUSIONS
  TSH levels show a statistically significant association to total cholesterol and LDL levels, but are not a good clinical predictor in this process. A cut-off point beyond which replacement therapy should be started to prevent occurrence of dyslipidemia cannot therefore be established.
authors.affiliation: Servicio de Medicina Interna, Hospital de Atuntaqui, Atuntaqui, Ecuador. vanealej_uio@yahoo.es
authors.forename: Vanessa
authors.initials: V
authors.lastname: Sarzosa Terán
authors.forename: María Augusta
authors.initials: MA
authors.lastname: Astudillo Calle
mesh_terms: D000328:Adult; D015415:Biomarkers; D015992:Body Mass Index; D002318:Cardiovascular Diseases / Q000453:epidemiology / Q000209:etiology; D002784:Cholesterol / Q000097:blood; D003430:Cross-Sectional Studies; D050171:Dyslipidemias / Q000097:blood* / Q000209:etiology / Q000517:prevention & control; D004484:Ecuador / Q000453:epidemiology; D005260:Female; D020249:Hormone Replacement Therapy / Q000379:methods*; D006801:Humans; D007037:Hypothyroidism / Q000097:blood* / Q000150:complications / Q000188:drug therapy / Q000453:epidemiology; D008077:Lipoproteins, LDL / Q000097:blood; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012307:Risk Factors; D012737:Sex Factors; D013972:Thyrotropin / Q000097:blood*; D013974:Thyroxine / Q000008:administration & dosage / Q000627:therapeutic use*
chemical_list: D015415:Biomarkers; D008077:Lipoproteins, LDL; D013972:Thyrotropin; D002784:Cholesterol; D013974:Thyroxine