Context: The Thr92Ala-DIO2 polymorphism may affect hypothyroid patients’ responses to levothyroxine (LT4) treatment. Objective: To study whether the Thr92Ala-DIO2 polymorphism affects hypothyroid patients’ responses to levothyroxine (LT4) treatment. Design: Secondary analysis of a randomized intervention study. Setting: Primary care center. Patients or Other Participants: 109 hypothyroid women aged 21-70 years with normal TSH levels grouped in homozygous Thr92-DIO2 (THR; n=39) and homozygous Ala92-DIO2 plus heterozygous (ALA; n=70) groups. Intervention: Change in LT4 dose. Main Outcome...