| Objective:Iodine Deficiency Disorders (IDD) is a kind of syndrome caused by insufficient synthesis of thyroid hormones due to iodine deficiency, which is characterized with mental and physical retardation. Brain damage is the main insult by iodine deficiency. The human potential and quality of life in Chinese children has progressively been improved after the implementation of Universal Salt Iodization (USI) since 1995. The mean IQ of children born after USI, who are living in severe IDD areas, has got 12 points increasing compared with those born before USI. China has reached the goal of virtual elimination of IDD at national level because households are fully covered by adequately iodized salt through market system. However, Re-emergence of IDD in some limited areas is recently discovered due to the failure of local iodized salt program and new cases of endemic cretinism were found in Baicheng and Wushi counties of Xinjiang Autonomous Region. Ministry of Health provided iodized oil capsules for pregnant women and lactating women in Xinjiang as urgent intervention. This study was concentrated on a survey of iodine nutritional status in babies and women in pregnancy and lactation, and brain development of babies after implementation of iodized oil program, compared with before the intervention. Therefore it is available to evaluate the effectiveness of iodized oil intervention and to explore possible problem as well as its further suggestion. Finally, To evaluate the status of iron nutrition in lactating women so as to search for other possible aetiological factor related to mental retardation.Methods:Stratified sampling method was used in this survey according to the geographic location of east, south, west and north of counties.10 schools of 8 townships were selected. In each school,10 children among each gender and age group from 8 to 10 years were selected with random sampling method. Total of schoolchildren were 300 individuals. With the simple random sampling method,306 pregnant women 233 infants aged 0-2 years and their mother were selected in 9 townships. The parameters of survey included the iodine concentration in drinking water (WI), coverage of iodized salt at household level (HIS), total goiter rate (TGR) and urinary iodine (UI). The other indices involved in thyroid function of women in pregnancy and lactation before and after implementation of iodized oil;serum ferritin,serum iron and total iron binding capcity of women in lactation, IQ in schoolchildren and psychomotor development of infants. Direct titration assay for testing the salt iodine, Colorimetric ceric-arsenic assay and Vitriolic ammonium assimilation were used for the determination of urinary iodine and water iodine. The size of thyroid gland was measured by palpation. The Combined Raven Test for Chinese Rural was used to test the intelligent quotient(IQ). The psychomotor development of infants was evaluated by Danver Development Screening Test (DDST).Results:The median of WI of two counties was 2.19μg/L. The coverage of HIS was 71.5%, however, the proportion of qualified iodizes salt was 68.6%. The medium of urinary iodine in school children was 103.7μg/L (The proption of less than 100μg/L was 47.8%, the proportion of less than 50μg/L was 28.0%), Baicheng and Wushi counties were 123.0μg/L(The proption of less than 100μg/L was 44.4%, the proption of less than 50μg/L was 33.3%)and 100.3μg/L(The proption of less than 100μg/L was 50.0%, the proption of less than 50μg/L was 24.5%),respectively. Before implementation of iodized oil capsules, the medium of urinary iodine in lactating women was 126.5μg/L. Moreover, the medium of urinary iodine in lactating women was only 74.6μg/L at Chaerqi Township and 84.8μg/L at Tuokexun Township. Implementation of iodized oil capsules after 4 months, the medium of urinary iodine the in lactating women, pregnant women and infants were 178.3μg/L,232.2μg/L and. 248.5μg/L,respectively. Implementation of iodized oil capsules after 9 months, the medium of urinary iodine the lactating women, was 133.8μg/L,. Moreover, the medium of urinary iodine in lactating women was only 44.2μg/L at Tuokexun Township and 99.7μg/L at Daqiao Township. The total goiter rate in school children was 14.3%, Baicheng and wushi counties were 10.8% and 16.6%,respectively. The mean IQ in school children was 80.6±11.6, Baicheng and Wushi cunties was 83.0±11.6 and 79.0±11.7, respectively. The proportion of mental retardation in school chilren (IQ≤69) was 13.0%, Baicheng and Wushi counties were 6.7% and 17.2%, respectively. Although the value of FT3, FT4 and TSH of pregnant women had a tendency of rise after implementation of iodized oil capsules compared to before, but there is no statistical significance. FT3 and TSH of lactating women after implementation of iodized oil capsules had not significant differences compared to before at the level of 0.05, however, FT4 had significant increase (P<0.05). The level of T3 and FT3 of infants who were identified to abnormal and suspicious by DDST were above the upper limitation of normal range. And the level of FT4 of them located in normal range, however, FT4 and TSH approached to the lower or upper limitation of normal range. SF of lactating women was lower. The level of SF of lactating women after implementation of iodized oil capsules had significant increase compared to those before implementation of iodized oil capsules at the level of 0.05. In addition, the proportion of abnormal and suspicious in infants by DDST was 21.2%, whose mother had not receive iodized oil capsules, and however decreased to 12.5% or 8.2% for the infants whose mother received the iodized oil capsules during pregnancy or lactation.Conclusion:This study might confirm the fact that there is also existence of mental retardation in children and infants, caused by iodine deficiency. The implementation of iodized oil capsules for pregnant women and lactating women could effectively prevent their infants from mental retardation. For administration, the better way should be dose at total of 400mg and divided into twice per year for pregnant and lactating women and interval was within 6 month. Lactating women had iodine deficiency combined with iron deficiency which might result in negative impact on the effectiveness of intervention. It is suggested that correction of iron deficiency at same time is exactly necessary for the population, in particular, the target groups who are at risk of iodine deficiency. |
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