Iodine excess discovered in children of the Bogotá savannah
UN/DICYT A research project carried out in the municipalities Chía and Bosa, on 6 and 15 year old students demonstrated excess iodine levels in children.
According to UNal Medicine Professor Roberto Franco the only confirmed role of iodine in the human body is related to thyroid hormone synthesis. Nevertheless, iodine excess produces goiter, hypothyroidism (low thyroid production) or hyperthyroidism (high thyroid production).
The research project included a total of 125 children, 47 from the municipality of Chia and 78 from the southern district of Bogotá known as Bosa. All children underwent an anthropometry, an echography and urine testing.
Colombia implemented a universal salt iodization system policy and was declared from free iodine disorders in 1998.
“However, although the country has been relatively successful with this law, it has failed because it is not only about ordering adding iodine to salt, but also carrying out epidemiological reviews, collecting samples to becoming cognizant if consumption is in the correct amounts,” said Franco.
Abnormal Thyroid-Stimulating Hormone (TSH) levels are above 5 uUI/ml. In the tests they discovered that 105 individuals (84%) had TSH levels under 5uUI/ml and 20 individuals (16%) had TSH levels greater than 5uUI/ml.
With respect to the clinical classification of goiter, it was assessed according to World Health Organization (WHO) criteria. Therefore they identified 15 individuals with non-palpable thyroid; 70 with palpable thyroid, greater than normal, but not visible with an extended head; and 8 individuals with palpable thyroid and visible when the neck was in a normal position.
According to the WHO classification no person with 3rd degree thyroid was discovered, in other words besides being palpable and visible at 10 meters (32.8 ft.) distance.
An optimal average urine iodine level (mcg/L) is between 100 and 199 and adequate iodine intake is between 150 and 299 (mcg/L).
The recommended daily iodine intake for adults is 150 mcg, 200 to 290 mcg for pregnant and lactating women, 50 mcg during the first year of life, 90 mcg for ages 1 through 6 and 120 mcg for children between 7 and 12 years of age.
Almost 90% of ingested iodine is excreted in the urine. Therefore iodine intake is frequently defined by iodine urine concentration.
In 2005 Colombia was placed on the list of countries in risk of excessive intake of iodine along with Uruguay, Paraguay, Honduras and Brazil. The average iodine level reported for Colombian was 409ug/L.
During the present study the average iodine intake was 401ug/L, which is in accordance and coincides with population in risk of excess.
According to WHO criteria, the average iodine urine concentration should be between 100 and 200μg/L. Therefore the study demonstrated that only 9.3% of school children are in this range and 5.3% of the population is in a deficient range.
Although the project shows iodine excess, which is an indirect marker of elevated iodine intake, Franco says that it was important for a country like Colombia to promulgate Act 44 of 1947 creating the former National Nutrition Institute as an entity of the Hygiene Ministry and determining iodization of salt. As opposed to countries like Greece or Italy who have yet to accept this regulation.
The initiative in Colombia, in his opinion, has avoided low levels of iodine in the Colombian population, which leads to issues such as severe mental retardation or cretinism (hypothyroidism).
Professor Franco is the Director of the UNal Thyroid Disease Research Center and the research project was performed along with Faculty of Medicine undergraduate Andrés Arturo Cuellar.