| Objective To evaluate the effect of prevention and control for IDD by salt iodization and find out key areas of iodine deficiency and the poor aspects in the work of IDD eliminating through monitoring and analyzing salt iodine and iodine nutritional level of local residents in each county of Ningxia. To inquire main influential factors of USI in key counties of iodine deficiency and to propose the pointed intervention measures for these counties to raise the coverage fraction of iodized salt. To explore combined ecology effect of iodine, fluorine, selenium on IDD and furthermore to provide geochemistry basis for adopting suitable and comprehensive strategies and measures for IDD prevention and control through investigating residents'intake status of these three elements in districts of iodine deficiency merging with fluorosis .Methods 288 resident salt samples, 60 urine specimens of 0~2 year-old infants, 100 urine specimens of 8~10 year-old elementary students were selected stochastically for iodine concentration determining in per of all 22 counties (cities, districts) of Ningxia in 2009, and the concentrations were compared with the data of 8 previous years and Nation IDD Elimination Standard. Meanwhile we investigated infants'breast feeding, mother taking iodine oil and so on and analyzed their effect on infants'urine iodine. In per of 5 key counties, we questioned 300 housewives in random on table salt, iodine-rich food, health education about IDD and the situation of social and economic, and then analyzed their impacts on the behavior of consuming iodized salt. In per of all 8 countries or towns of Yanchi County 25 drinking water, 80 urine specimens of 8~10 year-old elementary students were sampled randomly for detecting the density of iodine, fluorine, selenium in water and iodine in urine and analyzing their correlations.Results From 2001 to 2009, in Ningxia the coverage rate of iodine salt started being above 95% from 2005, and the qualified rate of iodine salt were above 90% in all 9 years, the rate of using qualified iodine salt started above 90% in 2004. And totally there were not identity (p<0.05). In 2009, at all the counties (cities, districts) the coverage rate of iodine salt were beyond 95% and the rate of using qualified iodine salt beyond 90% except Yanchi County, and the qualified iodine salt rate was higher than 90%. There was significant difference (p<0.05).At all 22 counties (cities, districts), the iodine medians of infants urine were in 140~300μg/L beside Longde County where it was 328.4μg/L, the proportions of urine iodine being lower than 50μg/L all were below 20% and higher than 300μg/L all were 10% or above, especially, Longde County was highest and it was 59.7%.The significant difference of infants urine iodine was among counties (p<0.05). The median of urine iodine correlated with that of salt iodine (p<0.05). Age, sex, breast feeding, mother taking iodine oil of infants were influential factors of infants urine iodine (p<0.05).At 21 counties (cities, districts) except Tongxin County which did not attend sampling, urine iodine medians of 8~10 years old students were in 148~300μg/L beside Yongning County where it was 309.8μg/L, the proportions of urine iodine being lower than 50μg/L all were below 20% and higher than 300μg/L 13 counties (cities, districts) were above 14%, especially, Yongning County was highest and it was 51.0%. The significant difference of students urine iodine was among counties (p<0.05). The median of urine iodine presented no relationship with that of salt iodine (p=0.572). From 1995 to 2008, salt iodine median, students urine median and the proportion of urine iodine being lower than 50μg/L were observed in Ningxia in 8 monitoring years and were correlated each other positively or negatively (p<0.05) . At 5 key counties of iodine deficiency in Ningxia, the percent of housewives using iodine salt were 94.4% and the one of women consuming iodized and non-iodized salt at the same time were 34.1%. In local housewives, the total rate of knowing IDD was 45.3% and total prevalence rate of behaviors sunch as having the way of obtaining IDD knowledge, putting the salt when cooking thoroughly and eating iodine-rich food was 55.6%. By single factor analysis, these factors affected housewives'behavior of using iodine salt such as the price and the way of obtaining salt, the status of marriage or nurture, the age, the degree of schooling, living in different counties, putting the salt when cooking thoroughly, having the way of obtaining IDD knowledge, eating or knowing some iodine-rich foods, knowing some IDD or the means for its prevention, understanding the meaning of iodine salt label (p<0.05). By multiple factor analysis, the status of marriage or nurture, the way of obtaining salt, putting the salt when cooking thoroughly and knowing iodine-rich food affected housewives'behavior of consuming iodine salt (p<0.05).Total content medians of iodine, fluorine, and selenium of drinking water which were selected from 8 countries or towns in Yanchi County were 30.6μg/L, 2.8mg/L, 4.7μg/L respectively, and there were significant concentration correlations between iodine, fluorine and selenium separately (p<0.01). The median of students urine iodine did not correlated to that of content common-factor of water iodine, fluorine and selenium at level of country or town (p=0.207).Conclusions In Ningxia, the level of USI enhanced gradually to high after 2000. The effect of prevention and correction for iodine deficiency by USI is nice, and current strategies and measures of USI are scientific and feasible. But present iodine content standard of 35±15mg/Kg should be adjusted down, and an excess of iodine intake should be monitored simultaneously when monitoring iodine deficiency.Non-iodized salt sold in markets of key counties of iodine deficiency, and need to strengthen the force of USI and non-iodized-salt attack in order to improve accessibility of iodine salt. Health education about IDD is very important because it affects housewives'behavior of using iodine salt. At the next step we should study effects and measures of using iodine-rich food.Ecologically,iodine, fluorine and selenium content of drinking water correlate with each other and not correlate with urine-iodine concentration of elementary students at Yanchi County. Fluorosis, IDD, the diseases which are related to excessive intake of iodine and selenium should be paid attentions by degrees from high to low, and decline of iodine and selenium should be avoided when practicing the project of reducing water fluorine at this county. |
PDF Full Text Request