The fight to eliminate iodine deficiency disorders is plagued by challenges in some western and central areas in China, a senior official said yesterday.

Wang Longde, vice-minister of health, said at a meeting on eliminating iodine deficiency in Beijing yesterday that seven provinces in western and central China had not succeeded in rooting out the condition.

Cases of mental retardation caused by iodine deficiency were identified last year in areas where consumption of iodized salt remains low, Wang said.