Thyroid hormone levels in Nigerians living in endemic goitrous and non-goitrous areas

Serum thyroxine (T-4) levels, triiodothyronine (T-3) sponge uptake and free thyroxine index (FTI) were determined in Nigerians living in endemic goitrous and non-goitrous areas. T-4 and FTI values in inhabitants of the non-goitrous area were found to be significantly higher and T-3% sponge uptake values significantly lower, than those from the goitrous area. The range of T-4 levels for normal subjects falls between 4.0 and 13.5 Ug%, that of T-3% uptake between 21.0 and 35.0 and that of FTI values between 1.25 and 4.60.