The supplementation of levothyroxine among indigenous people in endemic goitre areas: The impact of therapy.

was significantly reduced in the treatment group (baseline 42.8% vs final visit 13.0%, P < 0.0001); however, no significant difference was noted in the control group. Total T4 levels were increased in the treatment group ( P < 0.0001), while a significant reduction was noted in the control group ( P < 0.0001). Thyroid-stimulating hormone levels increased significantly in the treatment group following 1 year of intervention, while no significant changes were observed in the control group. As for the thyroid volume, both groups showed a significant increment following the intervention ( P < 0.0001). With respect to the nutritional status, the treatment group showed a significant increase in body weight following the intervention ( P < 0.05). In addition, the mid-arm circumference and body mass index also increased after 1 year of intervention. However, the control group showed a reduction in the waist‐hip ratio (P < 0.0001). Although there was no statistical difference in the waist‐hip ratio in the treatment group, there has been a significant reduction observed after 1 year of intervention. At 1 year, a reduction in skinfold thickness was noted in the treatment group while only the triceps and subscapular were increased in the control group. The body fat was decreased in the treatment group following 1 year of intervention ( P < 0.0001). No particular trend was noted in the urinary iodine excretion in the treatment group, but surprisingly, the levels were increased in the control group ( P < 0.0001). A significant increase in both systolic and diastolic blood pressures was observed in the treatment group following 1 year of intervention, but the controls showed a reduction in the systolic blood pressure ( P < 0.0001). Both groups showed a remarkable increase in mental performance, with a more pronounced effect in the treatment group (P < 0.05). The correction of iodine deficiency by levothyroxine supplementation has a short-term beneficial effect in reducing the prevalence of goitre and improving the mental ability among the Aborigines in endemic areas; however, proper monitoring and close supervision are needed to maintain compliance.