Thyroid function in a formerly goitrous community on Karkar Island, Papua New Guinea

During a survey of noncommunicable disease conducted on Karkar Island, Madang Province in 1986, measures of thyroid function were examined in adult residents of a formerly goitrous village (Gamog) and a neighbouring community (Marup) with no history of iodine deficiency or endemic goitre. In Gamog, almost 20% of males and almost 30% of females had palpable goitre (maximum prevalence at ages 35-54 years) but visible goitres were not encountered. However, thyroid function tests were generally similar in the two groups, suggesting that iodine deficiency is no longer an appreciable problem for adults in Gamog. The persistence of palpable goitre in this village is therefore likely to be a residual effect of previous iodine deficiency. Correction of the iodine deficiency in the Gamog community began with the program of iodized oil injections, which was undertaken in the 1970s. The current lack of iodine deficiency is probably due in the main to dietary change associated with the introduction of the cash economy. This effect may have occurred in many formerly goitrous communities in Papua New Guinea in recent years, although persistence of iodine deficiency in some parts of the country should not be discounted.