[Areas in Calabria with an elevated incidence of congenital hypothyroidism and iodine content of drinking water]

The screening of 128,442 newborns, carried out in our laboratory from 1/1/1991 to 31/12/1996, detected 51 cases of congenital hypothyroidism (CH). Due to a 98% coverage, the accurate regional map of CH distribution has been obtained. Two rural and/or mountainous areas showed high incidence, 1/1145 (area A) and 1/1193 (area B), respectively. The incidence of the remaining region is 1/4621, whereas the mean regional incidence is 1/2518. In order to verify a relationship between CH incidence and iodine deficiency, we analyzed the iodine concentration in drinkable water from 148 localities. The high incidence of CH in the A and B areas corresponds with a high percentage of water samples with iodine concentration2 micrograms/l (92% and 85% respectively). In 15 coastal localities with low CH incidence, iodine concentration was between 7 and 80 micrograms/l. For populations of the A and B areas showing dietary iodine deficiency due to local product diet, we suggest the iodine prophylaxis as soon as possible.