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China fights fall in IQ due to iodine deficiency

BMJ 1995; 310 doi: http://dx.doi.org/10.1136/bmj.310.6973.148 (Published 21 January 1995) Cite this as: BMJ 1995;310:148

More than eight million Chinese people have reduced IQ levels because of a shortage of iodine in their diets, according to a survey team from the China National Committee on Care for Children. Speaking last week Ji Xiaocheng, the senior member of the team, said that the potential for iodine deficiency in China was huge: about 400 million people—one in every three Chinese—live in regions where the natural iodine supply is far from sufficient.

Only recently has the Chinese government realised the cost of diseases caused by iodine deficiency. According to statistics from the Ministry of Health, over seven million Chinese people have goitre and 190000 suffer from congenital hypothyroidism.

Less visible, however, are the millions of people who may suffer subclinically. Mr Ji estimates that IQ levels could be reduced by over 10–15 points in the eight million people who he believes are affected by iodine deficiency.

Maternal hypothyroidism can cause miscarriages, growth retardation, and stillbirths. Each year six million babies are born in areas where there is a risk of iodine deficiency. Diseases caused by iodine deficiency are now seen not only as a health problem but also as a development issue for China. Not only rural areas are affected: people are at risk wherever natural iodine has been leached out of the ground and is no longer available in sufficient amounts in the food cycle.

A working conference on preventive health and hygiene for the Beijing municipal area was told this month that 5.5 million people under the capital city's government lived in risk areas.

Rather than target only the worst hit areas, the government has opted for a nationwide policy of iodising salt. The official government target is to iodise all edible salt by the end of 1996. Just over 40% of Chinese salt is currently iodised.

On paper China's salt industry is highly regulated. According to the rules, all producers and sellers of iodised salt must be licensed by the state. In practice, economic reform and the decentralisation of Chinese industry have encouraged many private producers and suppliers of salt to spring up. Non-regulated salt is popular because it is usually cheaper.

Figure1

China needs iodised salt on its food

Pang Peiyun, the state councillor responsible for the national programme, told officials last October to crack down on profiteers selling substandard and fake iodine salt.

Salt regulations are hard to implement even in Beijing. A report this month in the official newspaper Consumer Times said that half the sales of salt to the capital came from private producers. The report said that railway freight containing thousands of tons of refined salt was arriving in Beijing without official stamps from the China Salt General Corporation.—RICHARD TOMLINSON, freelance journalist, Beijing