Goiters May Reappear in Some Areas, Studies Show

In the 60 years since iodine was added to table salt in this country, goiters have virtually disappeared as a public health problem. But new studies warn that goiters may be coming back, at least in some parts of the U.S., caused not by iodine deficiency but by naturally occurring chemicals that are seeping into water supplies.

Some drinking wells are being contaminated when rain water percolates through coal, shale, and other rocks that contain organic material.

Once ingested, these chemicals apparently impair thyroid function, causing the gland to swell--a condition known as goiter. The most common chemical present is resorcinol.

Problem in Kentucky

So far in this country, the goiter problem has been identified only in Owsley County, Ky., where 36% of the children have developed goiters even though all of them had consumed more than enough iodine to prevent goiter, according to endocrinologist Eduardo Gaitan of the University of Mississippi Medical Center. The children are being treated with thyroid hormones.

But many other regions of the United States have geology that is similar to that of Owsley County, and there is a “strong possibility” that some of those areas may have similar health problems, Gaitan said.

“Unfortunately, there have been no good recent studies of the occurrence of goiter,” he said at a meeting of the American Chemical Society here last week.

Gaitan first identified the link between goiters and organic chemicals in the drinking water in South America. He said that in certain sections of Candelaria, Colombia, more than 30% of the children have goiters while in nearby parts of town the disease is virtually nonexistent. The same situation exists in at least 37 other communities in Colombia.

Chemicals in Grain

Furthermore, it is now believed, as many as 100 million people in the semi-arid regions of Africa and India also have thyroid disorders and goiters caused by the presence of such organic chemicals in millet, a grain that is a staple in their diet.

Previously, goiters were associated almost entirely with a lack of iodine in the diet.

In humans, the thyroid gland produces hormones required for many bodily functions. Goiters can lead to retardation of both mental and physical development. Later in life, goiter can be followed by cancers of the thyroid.

Goiters were common in the United States before 1926, affecting as many as 50% of the people in the northwest, around the Great Lakes and in Appalachia. The problem essentially disappeared after iodine was added to table salt.

As many as 300 million individuals in underdeveloped regions around the world still have goiters due to lack of iodine in their diet.

Gaitan, also of the Veterans Administration Hospital in Jackson, Miss., has been studying the incidence of goiter in Colombia since 1959, when he was a practicing physician there. He has continued those studies since moving to the United States 10 years ago.

It became clear recently, he said, that the incidence of goiter “correlated with geologic features,” particularly the presence of coal and shale.

Armed with this information, Gaitan teamed with geologists, chemists and other investigators from Oak Ridge National Laboratory, the University of Alabama School of Medicine at Birmingham, and the Royal Victoria Hospital in Montreal to study the water supply.

They found that the water from the affected regions of Kentucky and Colombia contained a large number of organic chemicals, especially resorcinol.

In separate studies, they found that resorcinol was at least 27 times as potent at inhibiting thyroid function as the most important anti-thyroid drug, PTU, which is used to treat patients with overactive thyroids. The chemical also caused goiters to develop in rats.

Not as Potent

Several other coal-derived chemicals in the water, they found, also produced goiters, although they were not as potent as resorcinol. Apparently, Gaitan said, no one has studied the health effects of these chemicals in humans.

Other chemicals in the water, particularly a group called phthalic acid esters, did not themselves cause goiters, but were converted into goiter-producing chemicals by bacteria that live in both the Kentucky and Colombia waters.

Millet does not contain resorcinol, said physician Robert C. Cooksey of the Jackson Veterans Administration Hospital, but it contains a group of chemicals called flavonoids that are converted to resorcinol when millet is boiled and stored. Millet is most commonly consumed in Africa and India, Cooksey said, after it is boiled for porridge or stored and fermented for beer.

In eastern Kentucky, the team also found certain other coal-derived chemicals in the water. Other scientists have shown, Gaitan said, that these chemicals can cause auto-immune thyroiditis when injected into rats, although there is no previous evidence of this effect in humans.

One third of the children in Owsley County with goiters also suffer from autoimmune thyroiditis, a disease in which the body’s immune system attacks the thyroid gland.

These latter chemicals were not found in the Colombian water. And no cases of thyroiditis were observed there.

Coal Processing Residue

Gaitan believes those particular chemicals originated in water runoff from coal processing plants.

Based on their findings, the group is planning an experiment to improve the water supply in Darien, Colombia, which comes from a deep well.

The group plans to install activated carbon filters to remove as much of the organic materials as possible from the water. The water will also be treated with iodine to kill the bacteria found in it.

There is no experimental evidence that removing chemicals from the water will undo the damage that has already been done, but Gaitan is optimistic because of a recent event in Candelaria.

In 1983, he said, the water supply was switched to an alternate source for about a year while the main well serving the town was dug deeper. During that period, the incidence of goiter among children dropped from 30% to 10%.

“Within six months after the town had switched back to its original water supply,” Gaitan said, “the incidence had gone back up to 32%.”

Recent Development

Gaitan has not proposed any corrective measures for Kentucky yet because, he said, “we do not want to make a statement not supported by clear scientific evidence.”

Epidemiologist Ward Hines of the Kentucky Department of Public Health said in a telephone interview that the department had just learned of Gaitan’s findings in the last couple of weeks.

He noted that the department had no plans for further action at present because “simple thyroid goiter is not necessarily a clinically significant illness. It’s not life-threatening, and we have many higher priorities.”

If the Colombian project shows promise, Gaitan said, “we will definitely put forward a plan for that area--probably individual filters for the drinking water in each house.”