Influence of thyroid hormones on biochemical parameters of liver function: a case-control study in North Indian population

Normal level of thyroid hormones is important for normal hepatic function and thyroid dysfunction may modulate metabolic function of liver. The purpose of this study is to determine whether liver function is associated with subclinical and overt hypothyroidism. Thyroid and liver function tests were evaluated in 47 patients with overt (TSH = 10.0 mIU/L) and 77 patients with subclinical hypothyroidism ( TSH 6.0-9.9mIU/L) and compared with 120 age-matched euthyroid controls. Subjects with overt hypothyroidism had significantly raised serum ALT, AST, ALP and total protein levels as compared to controls whereas subclinical hypothyroid patients had significantly increased levels of serum ALT, ALP and total protein. Further, TSH showed significant positive correlation with AST and ALP values whereas fT3 and fT4 had a negative correlation with AST in overt hypothyroidism. Thus, overt hypothyroid state is associated with significant derangement in biochemical parameters of liver function. Hence, liver function should be regularly monitored in hypothyroid patients.