ABSTRACT
Existen numerosos estudios que relacionan la deficiencia grave de yodo con la disminución de diferentes capacidades mentales superiores. En este trabajo se pretende conocer qué ocurre cuando la deficiencia de yodo no es tan grave como en los citados trabajos, sino que se trata de una falta de yodo leve o incluso moderada, y si los problemas comunes con una deficiencia grave de yodo (incluyendo el retraso mental) siguen apareciendo de una manera más sutil. Además, también interesa conocer si la metodología clásica (comparar zona yododeficiente contra zona no yododeficiente) es la más adecuada, proponiendo combinar esa agrupación por zonas con la yoduria presentada por los individuos de cada zona. Se evalúa cociente intelectual, capacidad manipulativa y verbal, atención, habilidad visomotora y comportamiento disruptivo, estudiadas muy pocas veces o ninguna en este tipo de investigaciones. La muestra la componen 760 escolares de la provincia de Jaén. Los resultados muestran que se encuentra un cociente intelectual más bajo en la zona yododeficiente y en niños con baja yoduria, cosa que no sucede en la zona yodosuficiente. También se ha visto asociado al nivel de yoduria el comportamiento disruptivo. Las otras variables medidas no se han asociado con déficit de yodo
An association between severe iodine deficiency and poor mental development has been found in many studies. We examined the relationship between moderate or mild iodine deficiency and intellectual capacity in order to determine whether problems common to severe iodine deficiency (including mental retardation) also emerge in a more subtle form. We also wished to know whether the classic methodology (comparing iodine-deficient zones with nondeficient zones) is the most adequate, and propose to combine this grouping by zones with urinary iodine presented by individuals in each zone. We measured IQ, manipulative and verbal capacity, attention, visual motor ability and disruptive behaviour, variables that have barely been studied in this kind of investigations. The sample comprised 760 schoolchildren from the province of Jaén (southern Spain). Our results show that children with low levels of iodine intake and with urinary iodine concentration lower than 100 µg/litre had a lower IQ and displayed more disruptive behaviour than children with high levels of the criteria. The other variables were not associated with iodine deficiency
Subject(s)
Humans , Male , Female , Child , Iodine Deficiency/complications , Mental Competency , Attention Deficit and Disruptive Behavior Disorders/etiology , Intellectual Disability/etiology , Visual Perception , Verbal Behavior , Psychometrics/instrumentationABSTRACT
An association between severe iodine deficiency and poor mental development has been found in many studies. We examined the relationship between moderate or mild iodine deficiency and intellectual capacity in order to determine whether problems common to severe iodine deficiency (including mental retardation) also emerge in a more subtle form. We also wished to know whether the classic methodology (comparing iodine-deficient zones with nondeficient zones) is the most adequate, and propose to combine this grouping by zones with urinary iodine presented by individuals in each zone. We measured IQ, manipulative and verbal capacity, attention, visual motor ability and disruptive behaviour, variables that have barely been studied in this kind of investigations. The sample comprised 760 schoolchildren from the province of Jaén (southern Spain). Our results show that children with low levels of iodine intake and with urinary iodine concentration lower than 100 microg/litre had a lower IQ and displayed more disruptive behaviour than children with high levels of the criteria. The other variables were not associated with iodine deficiency.
Subject(s)
Cognition Disorders/epidemiology , Intellectual Disability/epidemiology , Intelligence , Iodine/deficiency , Adolescent , Catchment Area, Health , Child , Female , Humans , Male , Neuropsychological Tests , Severity of Illness Index , Spain/epidemiologyABSTRACT
The association between iodine deficiency and poor mental and psychomotor development is known. However, most studies were undertaken in areas of very low iodine intake. We investigated whether a similar association is found in schoolchildren from southern Europe with a median urinary iodine output of 90 microg/liter. Urinary iodine levels were measured in 1221 children who also completed a questionnaire about their usual dietary habits. Intelligence quotient (IQ) was measured by Cattell's g factor test. IQ was significantly higher in children with urinary iodine levels above 100 microg/liter. The risk of having an IQ below the 25th percentile was significantly related to the intake of noniodized salt and drinking milk less than once a day. As expected, the risk of having an IQ below 70 was greater in children with urinary iodine levels less than 100 microg/liter. In conclusion, this study demonstrates that the IQ of schoolchildren in a developed country can be influenced by iodine intake. The results support the possibility of improving the IQ of many children from areas with mild iodine deficiency by ensuring an iodine intake sufficient to achieve a urinary iodine concentration greater than 100 microg/liter.
