title: Study of Insulin Resistance in Subclinical Hypothyroidism.
abstract: BACKGROUND
  Thyroid hormones influences glucose homeostasis. The association of insulin resistance in overt hypothyroidism is well proven, but very less information is available about insulin action on subclinical hypothyroidism.
  
  
  OBJECTIVE
  This study was done to evaluate the association between thyroid hormones and insulin resistance in subclinical hypothyroidism (SCH).
  
  
  METHODS
  Thirty subjects diagnosed as SCH and 30 age matched euthyroids were included. Serum TSH, FT3, FT4, fasting plasma glucose and insulin were estimated. Homeostasis Model Assessment was used to assess insulin resistance (HOMA- IR).
  
  
  CONCLUSIONS
  Serum TSH levels were significantly increased in SCH (14.20 ± 5.23 μU/ml) when compared with euthyroids (2.24 ±1.43μU/ml; P< 0.0001). Serum FT3, FT4 levels in SCH (2.96±0.80 pg/ml & 1.15 ± 0.52 ng/dl) were within the normal range. The mean insulin levels were significantly elevated in SCH (9.07±3.41 μU/ml) when compared with euthyroids (5.28± 2.18 μU/ml; P-value < 0.0001). The mean HOMA IR was significantly elevated in SCH (2.03 ± 0.95) when compared with euthyroids (1.05±0.45, P-value < 0.0001). TSH levels positively and moderately correlated with insulin (r= 0.43 P=0.03) and HOMA IR (r =0.48; P= 0.01). FT3 levels negatively and strongly correlated with insulin (r= -0.5, P=0.004) and moderately with HOMA IR (r= -0.38, P= 0.04). FT4 levels negatively and weakly correlated with insulin and IR (r= - 0.11, P=0.54; r= - 0.07, P=0.69 respectively). To conclude, SCH is associated with insulin resistance. Hence there is an increased risk of insulin resistance associated disorders such as metabolic syndrome, cardiovascular events in SCH.
authors.affiliation: Department of Biochemistry, Mediciti Institute of Medical Sciences, Hyderabad, India.
authors.forename: Sapna
authors.initials: S
authors.lastname: Vyakaranam
authors.affiliation: Mediciti Institute of Medical Sciences, Hyderabad, India.
authors.forename: Swati
authors.initials: S
authors.lastname: Vanaparthy
authors.affiliation: Department of Lab Mediciti hospitals, Hyderabad, India.
authors.forename: Srinivas
authors.initials: S
authors.lastname: Nori
authors.affiliation: Department of Biochemistry, Mediciti Institute of Medical Sciences, Hyderabad, India.
authors.forename: Satyanarayana
authors.initials: S
authors.lastname: Palarapu
authors.affiliation: Department of Biochemistry, Mediciti Institute of Medical Sciences, Hyderabad, India.
authors.forename: Aparna Varma
authors.initials: AV
authors.lastname: Bhongir
keywords: Insulin resistance (HOMA IR); Subclinical hypothyroidism (SCH)