Effect of 6 months L-thyroxin therapy on lipid profile of subclinical hypothyroidism

Sub-clinical hypothyroidism (elevated serum level of TSH with normal level of thyroid hormones) is common in adults, especially in women. Mild increasing level of TSH causes dyslipidemia and sub-clinical hypothyroidism may be associated with increased cardiovascular risk. Our study was designed to Assess the effect of early treatment with L-thyroxin on level of serum lipid in sub-clinical hypothyroidism patients.Subjects and In this study 40 sub-clinical hypothyroidism women patients referred to Endocrine Clinic of Golestan hospital of Ahvaz University of Medical Sciences (from 2005-2007) were evaluated. Hormon thrapy were introduced for each patient with 50-100 mg/daily of levothyroxine and adjusted with serum TSH level (TSH goal: 0.5-2.5 mIU/ml). The mean age of patients was (28.8 ± 10.8 years). The mean level of Tg was (141 ± 79.8 mg/dl) before treatment and decreased to (108 ± 75.8 mg/dl) 6 months after treatment (P = 0.006). Serum cholesterol level also significantly decreased after 3 and 6 months of treatment. It was 195.4 ± 41.1 mg/dl at baseline, 182.7 ± 39.9 mg/dl after 3 months and 172.8 ±48.8 mg/dl after 6 months of treatment (P=0.003, P=0.001, respectively). The mean serum level of LDL before treatment was 112.4 ± 38.5 mg/dl that showed significant decrease after 6 months of treatment 95.8 ± 41.8 mg/dl (P=0.026). The mean level of VLDL before treatment was 28.5 ± 15.09 mg/dl and 6 months after treatment decreased to 22.2 ± 15.9 mg/dl (P=0.009). There was no significant change, in HDL levels before and after 3 and 6 months of treatment (P>0.05).There was no significant relationship between age and TSH level and response to treatment (P>0.05). The patients who had higher level of Anti-TPO Ab showed significant decrease in serum level of Tg after treatment (P=0.04). Patients with positive titer of Anti-Tg Ab had significant decrease in serum level of LDL after 6 months of treatment (P=0.001). Positive CRP level was detected only in one patient. There were no significant changes in CRP after 3 and 6 months of treatment (P=0.32). Our results show that, treatment of subclinical hypothyroidism patients at any age and with any level of TSH causes decrease in cardiovascular risk factors, especially in patients with higher titer of Anti-TPO Ab and positive Anti-Tg Ab.