Author: Van Binh, T.; Kim Uoc, H.; Quang Toan, L.
In Vietnam, Iodine Deficiency Disorders (IDD) are a public health problem. The first nationwide survey of IDD in 1993 showed that 94% of the country population lived in iodine deficient areas. After the survey, a national IDD control program started to operate, first in mountainous provinces and afterwards extended to the whole country. Universal Salt lodization has been chosen as the basic measure for sustainable elimination of IDD nationwide. Five years after the commencement of the Program, the Nationwide survey of HDD in 1998 saw the improvement of IDD situation in Vietnam. However, mild IDD still existed in Vietnam with goiter prevalence in school children aged 8-12 years of 14.9% and 36.9% of urine samples below 10 ug/dl. Vietnam has set the goal of iodine deficiency elimination by the year 2000 with two criteria in the proportion of households using adequately iodized salt and the median value of urinary iodine of school children.
Purpose / Objective
In order to assess the results achieved in the period of 1996 to 2002, identify the current status of iodine deficiency disorders, constraining factors and specific areas where prevention activities of IDD should be strengthened in the next period, the national iodine deficiency disorders control program conducted this survey on iodine deficiency and mothers' knowledge, attitude and practice on IDD and iodised salt in the year 2000.
The specific objectives of the survey were to:
- identify proportions of households effectively using iodised salt by provinces, ecological regions and county; the roles of other iodised condiments such as iodised 'bot canh' and fish sauce in the prevention of iodine deficiency
- evaluate daily iodine intake of country population through value of urinary iodine of women having children less than age 5
- identify provinces reaching the program's target for the period 1995-2000
- identify the degree of contributing factors to usage of iodised salt and other condiments
A cross sectional household-based survey was designed to study mothers' knowledge, attitude and practice on iodised salt and IDD as well as their intake of iodine in the country. 61 separate surveys with the same methodology and questionnaires were conducted simultaneously in 61 provinces. The data of each survey are representative for each province. The data of ecological regions and county are computed from provinces' data taking into account the population differences of provinces. The survey design was based on the framework of the previous surveys done in 1998.
The study subjects were mothers having children age 5 or less. The subjects were interviewed in their homes and questioned on demography characteristics, knowledge of iodine deficiency and iodised salt, habits of purchase and usage of iodised salt and other condiments. Salt samples were tested by rapid test kit at the field and taken for titration in the labs of the provinces. Urine samples were taken for analyses of iodine concentration at the labs in Ho Chi Minh City, Quang Nam, Nghe An, Hoa Binh, Thai Nguyent and Hospital of Endocrinology.
There are some differences between the results of this national survey and the Multiple Indicator Cluster Survey II (MICS) which was also done in 2000 by the General Statistics Office. The MICS survey showed about 40 percent iodised salt coverage at the household level while this national survey showed 77 percent. It was discussed that this kind of difference probably stems from the different methods used for sample analysis. The MICS survey used detective test kits while the national survey used titration method (as in its previous survey).
Key Findings and Conclusions
1. The proportions of households with quality iodised salt was 77.8%. 'Bot cahn' is used mainly in Re River Delta, Northern mountain and Northern Central coast region with iodised bot cahn being used at the rates of 43.7%, 27.3% and 14.5% respectively. The proportions of its usage are less than 0.1% in the other regions. Iodised fish sauce is not common in all regions. This did not meet the IDD elimination goal of 90% of households although the usage of iodised salt has increased remarkably.
2. The median urine iodine level of 12.3 mcg/dl was above the internationally agreed minimum level of 10 mcg/dl. This is up from 3.2 mcg/dl in 1993. The percentage of women of childbearing age (15-49 years) with a urine level of less than 10 mcg/dl improved to 42.8% from 84% in 1993. The goitre rate among 8-12 year old school children was 10.2%.
3. There are still 34 provinces not achieving the program's target of 90% of effectively iodised salt coverage. Median urinary iodine level met the elimination goal; however, if we look at the situation from a regional or provincial angle, iodine deficiency is still a public health problem. The Mekong River Delta is identified as a region where IDD remains a serious issue in all the twelve provinces. All indicators were below the target level.
4. With regard to the influencing factors on usage of iodised salt and intake of iodine, the results show that literacy status and thorough awareness on IDD of the respondents influence positively the usage of iodised salt. 23.8% of respondents stated that iodised salt was unavailable while 17.9% responded it was too expensive. The price of iodised salt has a big influence on usage of iodised salt. In some regions the price of iodised slat is two fold that of the price of normal salt. The other influencing factors such as the interval between two successive buying of iodised salt or storage of iodised salt did not have a clear result.
To evaluate the role of sources supplying information on IDD, we found that television is the most important means accounting for 77.9%, radio and health worker are second and third at 57.5% and 51.2%. The other supplying sources such as newspaper, panel, respondents' children, etc. are less important.
We have to expand a distribution network of iodised salt nation-wide with a subsidy policy. It is necessary to ensure that iodised salt is available in any place and can be afforded. It is also necessary to supply a suitable supplementation of iodised salt for particular regions.
The content and pattern of the education program should be changed. We should focus on the harmfulness of iodine deficiency to mental retardation and brain damage rather than causing goitre. The media pattern should include tv, radio and health workers.
It is recommended that a survey that specifically addresses the serious problems of IDD in Mekong River Delta should be carried out to get a better understanding of the problem and to develop appropriate interventions.
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Health - Micronutrients IDD
National IDD Control Committee, Ministry of Health (Vietnam)