UNITED NATIONS (AP) -- Iodine deficiency, a major cause of mental disabilities and learning difficulties, will be eliminated in three years, U.N. officials and salt industry executives predicted Wednesday.

Two billion people - more than 30 percent of the world's population - still suffer from iodine deficiency, a disorder that can be alleviated by consuming iodized salt.

By 2005, the deficiency will be erased globally, culminating a 15-year effort by U.N. agencies, civil organizations, and salt producers - an achievement likened to eliminating smallpox, the United Nations Children's Fund said.

"By eliminating iodine deficiency, we are protecting newborns and children from brain damage and therefore are contributing to breaking the cycle of poverty," said Jack Ling, chairman of the International Council for Control of Iodine Deficiency Disorders.

The rapid success makes it "one of the most effective international public health campaigns in history," said UNICEF's Werner Schultink, chairman of the cooperative effort to rid the world of the deficiency.

In extreme cases, iodine deficiency can cause goiter and cretinism, a thyroid deficiency causing arrested mental and physical deformity. In its milder forms, it ripples across entire societies, with lesser degrees of mental impairment.

When prevalent, iodine deficiency can lower the average intelligence quotients of a population by as much as 13 percent, harming the economic development of nations, officials said. Average IQ rates range between 90 and 110, so a drops of 10 to 15 points can be devastating.

Iodine shortages strike hard at pregnant women and their children, causing miscarriages, stillbirths or neonatal deaths. Neuromuscular, speech and hearing abnormalities are common among children born to iodine-deficient mothers.

Since 1990, the percentage of households consuming iodized salt in developing nations has risen from 20 percent to 70 percent. Today, 91 million newborns around the world are protected, U.N. officials said.

In China, salt iodization covers 95 percent of the population of 1.3 billion, up from 50 percent 10 years ago.

But Russia, the Ukraine and Belarus are struggling with the problem because of the Chernobyl accident and what former world chess champion Anatoly Karpov, a UNICEF goodwill ambassador, described as a legacy of Soviet mentality.

In the middle of the 1930s, the Soviet Union began tackling the problem, and by 1967, Russia was producing 500,000 tons of iodized salt, and the Soviets declared the problem solved, Karpov said.

"Unfortunately people decided that if it was solved, then it was forever," he said.

So by the end of the 1980s, Russia was producing just 20,000 tons - 25 times less than it produced 35 years ago, as the area struggled with the effects of the 1986 Chernobyl accident, Karpov said.

The explosion of the Chernobyl reactor spread radiation readily absorbed by the thyroid gland, leading to cancers unless treated. Today, Russia produces 100,000 tons of the vital salt a year.

The battle against iodine deficiency has brought together nations such as Canada which contributed $ 20 million to the effort Wednesday; civic groups like Kiwanis which is giving $ 75 million to the effort; and salt manufacturers in North America, Europe and Asia.

Copyright 2002 The Associated Press. All rights reserved.