Iodine deficiency and its association with intelligence quotient in schoolchildren from Colima, Mexico

• Published in: Public health nutrition 2008-07, Vol.11 (7), p.690-698
• Main Authors: Pineda-Lucatero, Alicia, Avila-Jiménez, Laura, Ramos-Hernández, Rosa Isela, Magos, Clementina, Martínez, Homero
• Format: Article
• Language: English
• Subjects: Adolescent; anthropometric measurements; Anthropometry; boys; Child; child nutrition; Child Nutritional Physiological Phenomena - physiology; Children; Children & youth; cognition; Cross-Sectional Studies; deficiency diseases; disease prevalence; Dose-Response Relationship, Drug; Drinking water; Excretion; Female; Field study; fortified foods; girls; goiter; Goiter - epidemiology; Goiter - therapy; Goitre; Goitrogens; Human capital; Humans; Intelligence - drug effects; Intelligence - physiology; Intelligence quotient; Iodine; Iodine - administration & dosage; Iodine - deficiency; Iodine - standards; Iodine - therapeutic use; Iodine - urine; iodized salt; Male; Mexico; Mexico - epidemiology; nutrient deficiencies; Nutrient deficiency; Nutrition; Nutritional Requirements; Nutritional status; Nutritional Status - physiology; Prevalence; Regression Analysis; Salts; school children; Schools; Sodium Chloride, Dietary - administration & dosage; Sodium Chloride, Dietary - standards; Sodium Chloride, Dietary - therapeutic use; Thyroid; Thyroid gland; Thyroid Gland - anatomy & histology; Thyroid Gland - drug effects; Thyroid Gland - physiology; Water Microbiology; Well water
• ISSN: 1368-9800; 1475-2727; 1475-2727
• DOI: 10.1017/S1368980007001243

To determine the prevalence of iodine deficiency, its causes and its association with intelligence quotient (IQ) in Mexican schoolchildren. Cross-sectional analytical study, in which determinations of thyroid gland size, urinary iodine excretion, IQ, iron nutritional status, physical anthropometry, family consumption of goitrogenic foods, type/origin and iodine saturation of salt consumed at home and coliform organisms in drinking water were performed, and the association of each variable with IQ scores was evaluated by multiple regression analyses. Municipality of Cuauhtémoc, in Colima, Mexico (altitude: 600-2700 m above sea level). Sea salt is extracted manually nearby and often used for human consumption. Goitre remains present in the region despite over half a century of mandatory salt iodination in the country. Three hundred and three children, similar proportions of boys and girls, mean age 9.3 years, randomly selected from 19 public elementary schools. Overall goitre rate was 21.4%; low urinary iodine excretion was found in 19.5% of the children, high urinary iodine excretion in 32.0%. IQ scores were transformed into percentile values, with the following categorisation: < or = P5 (low IQ), 48.5%; > P5 to < or = P25 (below average), 24.2%; > P25 to < P75 (average), 18.8%; > or = P75 to < P95 (above average), 3.6%; > or = P95 (high IQ), 4.9%. Ninety-two per cent of the population used iodinated salt, but deficient iodine saturation (