Studies of the Control of Thyroid Function in Endemic Goiter in Eastern New Guinea

Abstract

Studies of the control of thyroid function in endemic goiter have been carried out in the rugged mountainous Huon Peninsula of Eastern New Guinea, where there is severe iodine deficiency. In 91 natives living in the endemic area the mean urinary iodine was 12[plus or minus]12 [mu]g/day compared with 49 [plus or minus] 55 in 31 coastal natives. Observations on I131 uptake in native villages with portable equipment revealed a higher 24-hr. I131 uptake in 59 goitrous natives (77 [plus or minus] 13%) than in 122 nongoitrous natives (67 [plus or minus] 20%). The serum PBI [protein-bound iodine] was lower in 85 goitrous natives (2.9 [plus or minus] 1.7) than in 119 nongoitrous natives (4.9 [plus or minus] 2.0). The T3 resin uptake was also lower in 80 goitrous natives (86 [plus or minus]15) than in 115 nongoitrous (94 [plus or minus] 18). Serum TSH [thyroid-stimulatory hormone] levels estimated using the McKenzie method revealed a significant elevation in goitrous but not in nongoitrous natives. Administration of T3 [triodothyronine] in a dosage of 120 [mu]g daily to 6 natives for 5 days was followed by a fall in 24-hr. I131 uptake from 81 to 41%. Observations in 43 natives who had received iodized oil injections 3 yr. before revealed a mean I131 uptake of 37 [plus or minus] 19% and urine iodine (in 29) of 35 [plus or minus] 25 [mu]g/day. Observations in 51 natives who had received oil 18 months before revealed an uptake of 30[plus or minus]19% and urinary iodine (in 18) of 119 [plus or minus] 114 [mu]g/day. Significant levels of serum TSH could not be detected in these natives nor in 16 goitrous natives who had shown significant regression of goiter following iodized oil injection 3 months before. It is concluded that the lower serum PBI and elevated serum TSH level in the goitrous compared with nongoitro?s natives indicate a failure in adaptation to iodine deficiency. The condition can, however, be readily reversed by correction of the Iodine deficiency with iodized oil.