Neuropsychological Studies in Iodine Deficiency Areas in China

Ma, Tai; Wang, Y. Y.; Wang, D.; Chen, Z. P.; Rai, S. P.

doi:10.1007/978-1-4613-0765-5_24

Cited by 14 publications

(6 citation statements)

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“…In humans, hearing loss has been found in cretinism (Trotter, 1960 ; DeLong et al, 1985 ; Morreale de Escobar et al, 2000 ), congenital in congenital hypothyroidism (Vanderschueren-Lodeweyckx et al, 1983 ; Rovet et al, 1996 ), and in Refetoff syndrome (Refetoff et al, 1967 ). Deafness may be complete in as many as 50% of patients suffering cretinism, in which no cochlear or brain stem response is seen (Halpern et al, 1989 ; Ma et al, 1989 ). Cochlear impairment and hearing loss with a decrease in hearing threshold by 20–60 dB was found in five different types of thyroid hormone receptor mutants (Ng et al, 2001 ; Rüsch et al, 2001 ).…”

Section: Discussionmentioning

confidence: 99%

Gestational and early postnatal hypothyroidism alters VGluT1 and VGAT bouton distribution in the neocortex and hippocampus, and behavior in rats

et al. 2015

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Thyroid hormones are fundamental for the expression of genes involved in the development of the CNS and their deficiency is associated with a wide spectrum of neurological diseases including mental retardation, attention deficit-hyperactivity disorder and autism spectrum disorders. We examined in rat whether developmental and early postnatal hypothyroidism affects the distribution of vesicular glutamate transporter-1 (VGluT1; glutamatergic) and vesicular inhibitory amino acid transporter (VGAT; GABAergic) immunoreactive (ir) boutons in the hippocampus and somatosensory cortex, and the behavior of the pups. Hypothyroidism was induced by adding 0.02% methimazole (MMI) and 1% KClO4 to the drinking water starting at embryonic day 10 (E10; developmental hypothyroidism) and E21 (early postnatal hypothyroidism) until day of sacrifice at postnatal day 50. Behavior was studied using the acoustic prepulse inhibition (somatosensory attention) and the elevated plus-maze (anxiety-like assessment) tests. The distribution, density and size of VGluT1-ir and VGAT-ir boutons in the hippocampus and somatosensory cortex was abnormal in MMI pups and these changes correlate with behavioral changes, as prepulse inhibition of the startle response amplitude was reduced, and the percentage of time spent in open arms increased. In conclusion, both developmental and early postnatal hypothyroidism significantly decreases the ratio of GABAergic to glutamatergic boutons in dentate gyrus leading to an abnormal flow of information to the hippocampus and infragranular layers of the somatosensory cortex, and alter behavior in rats. Our data show cytoarchitectonic alterations in the basic excitatory hippocampal loop, and in local inhibitory circuits of the somatosensory cortex and hippocampus that might contribute to the delayed neurocognitive outcome observed in thyroid hormone deficient children born in iodine deficient areas, or suffering from congenital hypothyroidism.

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Section: Discussionmentioning

confidence: 99%

Gestational and early postnatal hypothyroidism alters VGluT1 and VGAT bouton distribution in the neocortex and hippocampus, and behavior in rats

et al. 2015

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“…IQ distribution curves were shifted to the left and a meta-analysis confirmed an IQ deficit of 10 points in populations living in IDD areas (39). Most cases of mild mental retardation in IDD areas can be attributed to iodine deficiency (subcretins) (40).…”

Section: China's Experience In Monitoring and Elimination Of Iddmentioning

confidence: 99%

World Status of Monitoring of Iodine Deficiency Disorders Control Programs

Delange

Bürgi²,

Chen

et al. 2002

Thyroid

134

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Monitoring and evaluation are the last phases of a national iodine deficiency disorders (IDD) control program but among the most important. This paper summarizes the latest recommendations by the World Health Organization (WHO), the United Nations Children's Fund (UNICEF), and the International Council for Control of Iodine Deficiency Disorders (ICCIDD) about indicators and their normative values for monitoring the progress of IDD elimination and illustrates the successful monitoring programs in Switzerland and in China. Salt is the usual vehicle for iodine supplementation and quality control for iodine content can be assessed quantitatively by titration and qualitatively by simple test kits that can be used in the field. The most useful indicator of iodine nutrition is the median urinary iodine concentration. Thyroid size, especially by ultrasound, and neonatal thyrotropin (TSH) are also valuable. In Switzerland, access to iodized salt on a voluntary basis started in 1922. The initial level of iodization, 1.9-3.75 ppm iodine as potassium iodide (KI), was slowly increased to 15 ppm, and recently to 20 ppm, after careful epidemiologic and biologic monitoring. Elimination of IDD has been highly successful. The program costs US dollars 0.07 per year per person. In China, a national program of iodized salt (10-30 ppm) started in 1960 under the authority of the central government and rapidly expanded. National monitoring surveys have taken place every 2 years since 1993. Median urinary iodine, initially low, increased to 165 microg/L in 1995 and to 306 microg/L in 1999, prompting a decrease in the amount of iodine added to salt. The total goiter rate decreased to 20.4% in 1995 and to 8.8% in 1999. IDD can presently be considered as eliminated in China. Review of monitoring in the 128 other major countries affected by IDD shows extremely variable achievements, with evidence of IDD elimination in at least 18 additional countries. Some countries that were severely iodine deficient in the past are now exposed to iodine excess and risk its effects. Sustainable elimination of IDD is within reach and would constitute an unprecedented global success story in the field of noncommunicable diseases, but continuing vigorous action is required to attain this goal.

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“…Studies in Ecuador (Fierro-Benitez et al, 1989;Trowbridge, 1972) showed that correction of the maternal iodine deficiency before conception or in early pregnancy can improve the mental performance of offspring. Comparisons of primary school children in China, in areas with iodine deficiency versus areas with normal iodine intake (Ma, Wang, Wang, Chen, & Chi, 1989) and of goitrous vs. non-goitrous children in Chile (Muzzo, Levia, & Carrasco, 1987) showed better mental and psychomotor performance in the latter groups.…”

Section: Micronutrient Deficienciesmentioning

confidence: 99%