Iodine Status of School Children in the BjeloPoljeMunicipality
(2002)
M. Simić1, Z. Anđelković2, Lj. Žižić3, Lj. Nikoilić3, D. Đarmati4, K. Spasojević5, S. Obrenović6
1Federal Commission for Preventing Iodine Deficiency Disorders, 2Military Medical Academy, 3Health Institute Podgorica, 4 Public Health Institute of Serbia “dr. Milan Jovanović Batut”,5 Federal Bureau for Protection and Promotion of Health, 6 Food Examination Centre
Introduction
Iodine deficiency represents an important social-medical problem due to its diffusion and devastating effects on the health of people.
Worldwide, some 650 million people live with permanent iodine deficiency, of whom consequently some 20 million are mentally retarded.
Our country is in the group of countries that are extremely exposed to natural goitre factors. A research that had been carried out in the fifties of the 20th Century has shown that in the current territory of Serbia and Montenegro there were regions in which illnesses caused by iodine deficiency had a serious endemic character. The consequent disorders ranged from milder types of endemic goitre to occurrences of severe cretinism. Based on detailed research carried out by Ramzin and his associates, some 147 regions, then counties, were found to be endemic goitre areas, of which 41 had extremely prominent goitre [1.2]. The greatest frequency of goitre among school children in Serbia was registered in Gornja Jošanica - 90.0%, Badovinci - 88.3%, Novi Pazar - 84.5%, and Prijepolje, while in Montenegro it was registered in Bjelo Polje, Rožaje and Andrejevica [2].
Research carried out by Prof. Gušić in 1955 in the Bjelo Polje area showed that goitre was prominent due to iodine deficiency and the frequency was greater among the respondents living in areas along the river Lim than those living in the mountainous areas. The research discovered some 200 individuals with prominent signs of endemic cretinism[3].
Taking into consideration the social-medical significance of disorders caused by iodine deficiency and the established frequency of the illnesses, preventive measures had been necessary to control and eliminate the problem. Similar to actions undertaken in other countries, an iodine prophylaxis was carried out, i.e., iodising of salts for human consumption.
The implementation of this useful measure resulted in a significant reduction of the frequency of goitre and the elimination of more serious types of goitre and cretinism. This was verified by the research carried out by Dr. Ivović in 1980 and 1981 in the area of BjeloPolje. However, despite the extremely positive effects of iodine prophylaxis, goitre had not been eliminated. This was confirmed by the results of a research carried out among school children of the 7 to 15 year age group in 2000 in Montenegro. The research showed that in the territory of Montenegro there was a “mild level” of iodine deficiency disorders(goitre frequency 27.3%, median of the urine iodine excretion 83.00 mcg/l), [3]. These results also pointed out that the frequency of goitre in the Bjelo Polje area was 48.8%.
A research carried out in Serbia in 1997 on a representative sample of school children of the 7 to 15 year age group established the frequency of goitre to be 2.35 %, i.e., that the median of iodine excretion in urine was 153.00 mcg/l [4]. A research was carried out in the territory of the TimokKrajinaCounty in 2001 that showed the frequency of goitre to be 1.0%, while only 7.0% of the children were found to have the concentration of iodine excretion in urine under 100.00 mcg/l [5]. These results showed that iodine deficiency disorders in Serbia have been eliminated, i.e., that there is a satisfactory inclusion of iodine in nutrition.
Taking into consideration that the inclusion of iodine in nutrition in Serbia was satisfactory and the fact that it was not in Montenegro, the necessity emerged to discover the reason for such a situation through the monitoring of goitre frequency, especially in the imperilled areas (Bjelo Polje).
Research Goal
The research goal was to establish the iodine status of school children in the Bjelo Polje municipality.
Material and research methods
In accordance with the recommendations from WHO, UNICEF and ICCIDD, the research encompassed school children from 7 to 15 years old by establishing the volume of the thyroid gland applying the ultrasound method and the measurement of the concentration of iodine in urine. The research criteria to establish iodine deficiency were: prevalence of the median volume of the thyroid gland in relation to the childpopulation with normal inclusion of iodine in nutrition, and the median of excretion of iodine in urine below 100.00 mcg/l [6].
The success of the Programme of Universal Iodising of Salts was established on the basis of criteriaof salt percentage with satisfactory iodine contents.
Organisation and research
The research was carried out by the team visiting selected schools and examining the children in situ. Portable ultrasound diagnostic equipment was used, as well as equipment for taking and storing urine samples (urine glasses, portable refrigerator) and questionnaires for data on the respondents and research results. The research was conducted from 8-11 October 2002.
Respondents and area of research
In accordance with the recommendations from WHO, UNICEF and ICCIDD, a statistically valid bulk of the sample was determined, i.e., the number of respondents and their distribution. The sample was determined in accordance with the expected prevalence of iodine deficiency disorders, the relative precision, the factor of desirable effect, safety interval and the number of respondents[6].
The research was carried out in the Bjelo Polje municipality and included 312 children from 7 to 15 years old.
Volume of the thyroid gland
The volume of the thyroid gland was determined by an ultrasound examination of the gland on children lying on their back, with hyper extended necks7.
The portable ultrasound instrument “Aloka SSD-500” was used, with a linear sounder operating at the 7.5 MHz frequency. Each child was examined with the maximum width (b) and thickness (v) of the lobus at the transverse section and the length (a) at the longitudinal section, with each lobus being separately examined.
The volume of the thyroid gland was calculated according to the formula:
V = a b v 0,479
and expressed in millilitres (ml), while the other parameters were expressed in centimetres(cm). The volume of the thyroid gland was presented by the addition of the volumes of both lobuses, while the volume of the isthmus was not taken into consideration8.
Excretion of iodine though urine
The urinary excretion of iodine was determined by a method based on the digesture of urine with chloric acid and the colorimetric detection of iodine by the reduction of ceric ammonium sulphates9. The obtained values of the excreted iodine in urine were expressed in mcg/l of urine.
Urine samples were taken from 113 children. They were taken in 10 ml PVC bottles and preserved and transported in a portable refrigerator until they were frozen and stored waiting to undergo analytical diagnostics.
.
Control of the degree of iodisation of kitchen salts
Salt samples were taken from the households of children included in the research. Salt samples were taken in 100 gr plastic jars and laboratory examinations of the iodine contents were carried out in them. The determining of the iodine value in kitchen salt was carried out with the application of the titrimetric method with sodium-tiosulphate[10].The obtained values were expressed in milligrams of potassium iodide per one kilogram of salt (mg KJ/kg salt).
The obtained results will be compared with the Code on Quality of Kitchen Salt and Salt for the Food Industry that prescribes the quantity of iodine in these salts [11].
Questionnaire on respondent
A questionnaire was completed for each respondent during the examination. The questionnaire contained data about the respondent (name and surname, date of birth, gender, place of residence and name of school) and results of the ultrasound exam of the thyroid gland (dimensions of the lobus), as well as the obtained values of the excreted iodine in urine and the iodine content in the salt.
Statistical processing
The obtained results were processed and analysed in relation to the gender and age of the examined children, as well as the type of settlement (urban or rural), in accordance with the recommendations and criteria of the WHO and ICCIDD [6].
All the obtained research results were entered into a Microsoft Excel database and statistically processed by the SPSS statistical package.
The values of the volume of the thyroid gland were statistically processed and given as an average value, standard deviation and median.
The values of the excreted iodine in urine were presented and processed through the median value.
Research Results
The research was carried out with 312 school children from 7 to 15 years old in the Bjelo Polje municipality (Chart 1.).
Chart 1. Territory of the Bjelo Polje municipality
Kragović, 1991
Of the total examined children, 157 (50.32%) were boys and 155 (49.68%) girls. (Table 1.).
Table 1. Age and gender proportion of the respondents
Age(years) / Gender
Boys / Girls / Total
N / % / N / % / N / %
7 / 18 / 11.46 / 19 / 12.26 / 37 / 11.86
8 / 17 / 10.83 / 22 / 14.19 / 39 / 12.50
9 / 18 / 11.46 / 17 / 10.97 / 35 / 11.22
10 / 18 / 11.46 / 21 / 13.55 / 39 / 12.50
11 / 25 / 15.92 / 20 / 12.90 / 45 / 14.42
12 / 19 / 12.10 / 15 / 9.68 / 34 / 10.90
13 / 19 / 12.10 / 22 / 14.19 / 41 / 13.14
14 / 17 / 10.83 / 14 / 9.03 / 31 / 9.94
15 / 6 / 3.82 / 5 / 3.23 / 11 / 3.53
/ 157 / 100.00 / 155 / 100.00 / 312 / 100.00
The majority of the children that were examined -45 (11.42%) - were 11 years old, while only 11 (3.53%) were 15 years old. Of the total number of examined children, 157 (50.32%) were from urban and 155 (49.68%) from rural settings. (Table 2.).
Table 2. Age and gender proportion of respondents in relation to setting
Age(years) / Urban settlement / Rural settlement
Boys / Girls / Total / Boys / Girls / Total
7 / 9 / 10 / 19 / 9 / 9 / 18
8 / 9 / 11 / 20 / 8 / 11 / 19
9 / 11 / 8 / 19 / 7 / 9 / 16
10 / 9 / 9 / 18 / 9 / 12 / 21
11 / 15 / 9 / 24 / 10 / 11 / 21
12 / 9 / 6 / 15 / 10 / 9 / 19
13 / 7 / 11 / 18 / 12 / 11 / 23
14 / 11 / 5 / 16 / 6 / 9 / 15
15 / 3 / 5 / 8 / 3 / 0 / 3
/ 83 / 74 / 157 / 74 / 81 / 155
Table 3. Average value I standard deviation of the gland volume in relation to gender and age of respondent
Age(years) / Gender
Boys / Girls / Total
7 / 2.56 / ± / 1.07 / 2.14 / ± / 0.55 / 2.34 / ± / 0.86
8 / 2.52 / ± / 0.74 / 2.53 / ± / 0.77 / 2.53 / ± / 0.75
9 / 2.60 / ± / 0.64 / 2.60 / ± / 0.50 / 2.60 / ± / 0.57
10 / 3.34 / ± / 1.45 / 3.36 / ± / 1.00 / 3.35 / ± / 1.21
11 / 3.35 / ± / 0.72 / 3.24 / ± / 0.86 / 3.30 / ± / 0.77
12 / 4.34 / ± / 1.32 / 4.60 / ± / 1.48 / 4.46 / ± / 1.38
13 / 5.04 / ± / 1.82 / 5.02 / ± / 2.38 / 5.03 / ± / 2.11
14 / 5.70 / ± / 2.43 / 6.38 / ± / 1.79 / 6.01 / ± / 2.16
15 / 6.42 / ± / 0.94 / 7.13 / ± / 4.10 / 6.74 / ± / 2.71
/ 3.26 / ± / 1.01 / 3.36 / ± / 1.22 / 3.31 / ± / 1.14
Table 3. presents the obtained results of the examination of the volume of the thyroid glands, expressed through the average value and standard deviation in relation to the gender and age of the child. The volume of the thyroid gland was expressed through the average value (SV+/-SD) and among boys ranged from 2.56+/-1.07 ml in the 7th year up to 6.42+/-0.94 ml in the 15th year, and among girls from 2.14+/-0.55 ml in the 7th year and up to 7.13+/-4.10 ml in the 15th year.
The obtained average values of the thyroid gland volume significantly increase with age both among girls and boys, regardless whether they are from rural or urban settings. The obtained values of the gland volume are bigger among children living in urban settings than those of rural children. (Table 4.)
Table 4. Average value and standard deviation of gland volume according to gender and age of respondents in relation to setting
Age(years) / Urban settlement / Rural settlement
Boys / Girls / Total / Boys / Girls / Total
7 / 3.02 / ± / 1.36 / 2.40 / ± / 0.45 / 2.69 / ± / 1.01 / 2.11 / ± / 0.33 / 1.84 / ± / 0.52 / 1.98 / ± / 0.44
8 / 2.74 / ± / 0.91 / 2.61 / ± / 0.67 / 2.67 / ± / 0.77 / 2.27 / ± / 0.41 / 2.45 / ± / 0.88 / 2.37 / ± / 0.71
9 / 2.54 / ± / 0.70 / 2.81 / ± / 0.60 / 2.65 / ± / 0.66 / 2.69 / ± / 0.56 / 2.42 / ± / 0.33 / 2.54 / ± / 0.45
10 / 2.94 / ± / 0.53 / 3.60 / ± / 1.02 / 3.27 / ± / 0.86 / 3.74 / ± / 1.96 / 3.18 / ± / 1.00 / 3.42 / ± / 1.47
11 / 3.26 / ± / 0.54 / 2.82 / ± / 0.68 / 3.10 / ± / 0.62 / 3.48 / ± / 0.94 / 3.58 / ± / 0.86 / 3.53 / ± / 0.88
12 / 5.17 / ± / 1.39 / 3.79 / ± / 0.75 / 4.62 / ± / 1.34 / 3.60 / ± / 0.67 / 5.15 / ± / 1.63 / 4.33 / ± / 1.43
13 / 4.45 / ± / 2.15 / 5.25 / ± / 2.09 / 4.94 / ± / 2.09 / 5.39 / ± / 1.59 / 4.79 / ± / 2.72 / 5.10 / ± / 2.17
14 / 5.88 / ± / 2.00 / 6.76 / ± / 2.27 / 6.15 / ± / 2.05 / 5.37 / ± / 3.26 / 6.17 / ± / 1.58 / 5.85 / ± / 2.32
15 / 6.93 / ± / 0.67 / 7.13 / ± / 4.10 / 7.05 / ± / 3.13 / 5.90 / ± / 0.99 / 0.00 / ± / 0.00 / 5.90 / ± / 0.99
/ 3.36 / ± / 0.93 / 3.38 / ± / 1.15 / 3.38 / ± / 1.14 / 3.14 / ± / 0.97 / 2.69 / ± / 0.87 / 3.18 / ± / 0.99
The second variable used to determine disorders caused by iodine deficiency is the concentration of iodine excretion in 113 samples of urine. Of the total number, 55 (48.67%) samples were taken from boys and 58 (51.33%) from girls (Table 5.).
Table 5. Value of excreted iodine in urine in relation to gender
Value of iodine in urine(mcg/l) / Urine samples
Boys / Girls / Total
N / % / N / % / N / %
<20 / 0 / 0.00 / 5 / 9.09 / 5 / 4.42
20-49 / 7 / 12.07 / 8 / 14.55 / 15 / 13.27
50-99 / 22 / 37.93 / 13 / 23.64 / 35 / 30.97
>100 / 29 / 50.00 / 29 / 52.73 / 58 / 51.33
58 / 100.00 / 55 / 100.00 / 113 / 100.00
Table 6. Value of excreted iodine in urine in relation to gender and setting
Value of iodine in urine(mcg/l) / Urban setting / Rural setting
Boys / Girls / Total / Boys / Girls / Total
N / % / N / % / N / % / N / % / N / % / N / %
<20 / 0 / 0.00 / 2 / 7.69 / 2 / 3.57 / 0 / 0.00 / 3 / 10.34 / 3 / 5.26
20-49 / 4 / 13.33 / 2 / 7.69 / 6 / 10.71 / 3 / 10.71 / 6 / 20.69 / 9 / 15.79
50-99 / 9 / 30.00 / 3 / 11.54 / 12 / 21.43 / 13 / 46.43 / 10 / 34.48 / 23 / 40.35
>100 / 17 / 56.67 / 19 / 73.08 / 36 / 64.29 / 12 / 42.86 / 10 / 34.48 / 22 / 38.60
30 / 100.00 / 26 / 100.00 / 56 / 100.00 / 28 / 100.00 / 29 / 100.00 / 57 / 100.00
The obtained results of the concentration of excreted iodine in urine ranged from 1.0 to 314.00 mcg/l, while the value of the iodine median in urine amounted to 100.00 mcg/l of urine. Of the total samples of urine that were taken, only 1.7% were registered to have a value of excreted iodine below 20.00 mcg/l, 2.8% samples 20.00- 49.00 mcg/l, and 16.3% samples 50.00-99.00 mcg/dl of urine (Table 5.). The obtained results of the excreted iodine in urine in relation to the gender of the respondents and their setting are given in Table 6.
Table 7. Value of iodine in kitchen salt samples
Contents of iodine in salts / Number of salt samplesN / %
< 12 / 11 / 35.48
12-18 / 16 / 51.61
> 18 / 4 / 12.90
31 / 100
The examination of the contents of iodine in samples of kitchen salt taken from the houses of the respondents is presented in Table 7. Of the total 31 samples that were taken, the value of iodine below the legally prescribed values were found in 11 (35.48%) samples, while satisfactory values were found in 16 (51.61%) samples and legally prescribed values of iodine in salt were found in 4 samples (12.90%).
Discussion
The research was carried out among 312 school children from 7 to 15 years old in the municipality of Bjelo Polje. Of this number of examined children, 157 (50.32%) were from urban and155 (49.68%) from rural settings. Regarding gender representation, 157 (50.32%) were boys and 155 (49.68%)girls.
Table 8. Average value of the thyroid gland volume among school children in this research and researches carried out by Simić, Vitti, Gutekunst and Kurtoglu (ml)
Age(years) / This research / Vitti and associates / Simić and associates / Kurtoglu and associates / Gutekunst and associates
Sweden / Germany
7 / 2.34 / 3.1 / 3.52 / 3.86 / - / -
8 / 2.53 / 3.3 / 3.82 / 4.4 / - / -
9 / 2.60 / 3.6 / 4.31 / 5.18 / - / -
10 / 3.35 / 4.0 / 4.74 / 4.92 / - / -
11 / 3.30 / 4.9 / 5.23 / 5.97 / - / -
12 / 4.46 / 5.3 / 5.86 / 6.57 / - / -
13 / 5.03 / 6.1 / 6.21 / 8.89 / 4.2 / 9.3
14 / 6.01 / 6.3 / 7.04 / 9.53 / - / -
15 / 6.74 / - / 7.47 / 10.63 / - / -
The obtained average values of the thyroid gland volume of school children in this research are smaller than those obtained by Vitti and associates12in Italy, Simić and associates 4in Serbia, Kurtoglu and associates 13in Turkey and Gutenkunst and associates in Sweden and Germany14. It should also be kept in mind that all these researches were carried out in regions that had a satisfactory iodine status.
The obtained values of the median of excreted iodine in urine was 100.00 mcg/l of urine, while the values of excreted iodine in urine that were less than 50.00 mcg/l were found among 17.70% urine samples that result in a satisfactory iodine status of the population under research 11.
Conclusion
The obtained results of the thyroid gland volume and iodine excretion in urine in this research point out that the Bjelo Polje municipality is an area with a satisfactory inclusion of iodine in nutrition of the population under research. The stricter measures undertaken to implement the Programme of Universal Salt Iodisation during these last years have proven to be effective in this region considering that the research carried out in Montenegro in 1999 had registered a “mild level” of disorders caused by iodine deficiency.
Literature
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