LONGITUDINAL-STUDY ON GOITER PREVALENCE AND GOITROGEN FACTORS IN NORTHEASTERN SICILY

A longitudinal study was carried out in an area of endemic goiter of n orth-eastern Sicily. Three different surveys (in 1977, 1983 and 1994) evaluated the epidemiological prevalence of goiter in schoolchildren o f the endemic area (towns of Bronte, Troina and Maniaci) in comparison to an iodine sufficient control area (Catania). Biochemical studies w ere also performed on urinary iodine and thiocyanate (SCN) excretion a nd I-131 thyroid uptake. In the town of Troina an experimental program of active iodine prophylaxis was carried out from 1979 to 1987 by iod inating the municipal water supply. The aim of this study was to evalu ate the effect of an active iodine prophylaxis program in comparision to the ''silent iodoprophylaxis'' due to improved economic conditions and widespread introduction of industrially produced food. In the 1977 -94 period a significant decrease of goiter prevalence in schoolchildr en was observed in all areas where no active iodoprophylaxis had been introduced. An abnormal prevalence of goiter, however, was still prese nt in Bronte (12.1%) and Maniaci (25.9%) schoolchildren in respect to Catania (0.7%). In Troina, goiter prevalence decreased from 52.2 to 6. 1% after only five years of active iodine prophylaxis (1983). It incre ased to 8.4% seven years after the program was discontinuated (1994). In all areas studied average urinary iodine excretion increased by 70- 100 mu g/day except in the more rural area at Maniaci. During the same period urinary SCN values decreased by 30-40% and were lower in Troin a (non volcanic soil) than in other towns studied. The balance beetwee n iodine and SCN intake appears a relevant factor in the etiology of e ndemic goiter in these areas and the iodine/SCN ratio inversely correl ated with goiter prevalence. The persistence of endemic goiter in spit e of the important changes in life style and socio-economic conditions if compared to the dramatic amelioration obtained by an active iodine prophylaxis program, confirms the inadequacy of the silent iodine pro phylaxis, and further supports the need of an immediate introduction o f active iodine prophylaxis in the areas of endemic goiter in Sicily. (C) 1996, Editrice Kurtis