Epidemiological study of risk factors for goiter among primary schoolchildren in southern Ethiopia
Eskinder Wolka, Solomon Shiferaw, and Sibhatu Biadgilign Abstract Background. Iodine-deficiency disorders are a major public health problem all over the world. Goiter is the most visible manifestation of iodine-deficiency disorder. Goiter rate is useful to assess the long-term impact of iodine-deficiency disorders. Objective. To determine the risk factors for goiter in primary schoolchildren in southern Ethiopia. Methods. A cross-sectional study on a sample population of 270 children 6 to 12 years of age with goiter and 264 without goiter was conducted in a primary school in Sodo Town, southern Ethiopia. All students in each class were examined for the presence of goiter and classified based on World Health Organization criteria. For each child with goiter, the next child without goiter was selected from the same class. Multivariate logistic regression analysis was employed to determine the effect of independent variables on the goiter rate. Results. A total of 534 participants (270 children with goiter and 264 without goiter) were included. Although the difference was not significant, the prevalence of goiter was higher among girls than among boys (54.8% vs. 45.2%), and the prevalence in both sexes increased with age. In the multivariate logistic regression model, consuming common goitrogenic foods (adjusted OR, 1.9; 95% CI, 1.2 to 2.9) and drinking water from the river (adjusted OR, 2.5; 95% CI, 1.2 to 4.9) were independently associated with goiter. Eskinder Wolka is affiliated with the Department of Public Health, College of Medical and Health Science, Wolaita Sodo University, Wolaita Sodo, Ethiopia; Solomon Shiferaw is affiliated with the School of Public Health, College of Health Sciences, Addis Ababa University, Addis Ababa, Ethiopia; Sibhatu Biadgilign is affiliated with the Department of Epidemiology and Biostatistics, College of Public Health and Medical Science, Jimma University, Jimma, Ethiopia. Please direct queries to the corresponding author: Sibhatu Biadgilign, Department of Epidemiology and Biostatistics, College of Public Health and Medical Science, Jimma University, PO Box 24414, Addis Ababa, Ethiopia; e-mail: [email protected].
20
Conclusions. Goiter rate is significantly associated with consumption of goitrogenic food items in the area and contaminated drinking water. Creating awareness in the community about the consumption of food items and provision of tap water by concerned bodies in the area is recommended to prevent iodine-deficiency disorders.
Key words: Children, Ethiopia, goiter, risk, school Introduction Iodine is an important micronutrient required for human nutrition. Iodine deficiency disorders are a major public health problem all over the world. The effects of iodine-deficiency disorders vary according to nutritional status. Among children, some of the major effects are impaired mental and physical development, mental retardation, physical deformities, and cretinism [1]. Overall, iodine deficiency affects the socioeconomic development of a community [2]. Iodine deficiency is estimated to cause 1.8 million disabilityadjusted life years (DALYs) lost in children younger than 5 years in the 36 focus countries [3]. Iodine deficiency affects an estimated 60 million school-age children in the developing world and is associated with lower test scores and cognitive abilities. Studies indicate that between 35% and 70% of schoolchildren in developing countries may be iodine deficient [4]. In a survey conducted among schoolchildren and household members in Ethiopia, the national goiter prevalence rate ranged from 0.4% to 66.3%, with a mean value of 35% [5, 6]. The prevalence of iodinedeficiency disorders among schoolchildren was 53.3%. The prevalence was higher in girls (56.1%) than in boys (50.8%) [7]. Goiter prevalence in four regional states of Ethiopia—Southern Nation Nationalities and People Region (SNNPR) (the area of the present study), Oromia, Benshangul-Gumuz, and Tigray—was greater than 30%, indicating severe iodine deficiency. According to the third (2007) edition of WHO/UNICEF/
Food and Nutrition Bulletin, vol. 35, no. 1 © 2014, The Nevin Scrimshaw International Nutrition Foundation.
21
Risk factors for goiter in Ethiopia
ICCIDD [8], iodine-deficiency disorders are a major public health problem in Ethiopia. Even though inadequate intake of iodine is the principal cause of iodine-deficiency disorders, goitrogens such as cassava, millet, soybean, bamboo shoot, turnip, and kale, which interfere with the metabolism of iodine and the formation of thyroid hormone, are also implicated [1, 2, 6, 9]. Contamination of drinking water by microbes and other associated nutritional deficiencies, such as vitamin A deficiency, protein–energy malnutrition, and iron-deficiency anemia, are among the environmental and nutritional factors that contribute to the occurrence of iodine-deficiency disorders [10]. Goiter is the most visible manifestation of iodine-deficiency disorders. Goiter rate is useful to assess the long-term impact of iodine-deficiency disorders [11]. Risk factors for goiter are those that do not seem to be a direct cause of the disease, but seem to be associated in some way. Having a risk factor for goiter makes the chances of getting the condition higher, but does not always lead to goiter [12]. The main objective of this study was to determine the risk factors for goiter in primary schoolchildren in southern Ethiopia.
Materials and methods
schools from the town by a purposive sampling technique, considering the large numbers of students needed to get the desired sample size. The number of students and a list of students were obtained from the school. All students in each class were examined for the presence of goiter and classified based on World Health Organization (WHO) criteria until the required sample size was reached. Children who had goiter were given identification numbers. For each child with goiter, the next nearest child without goiter was selected from the same class for comparison, irrespective of the sex of the child. Measurements
Data were collected with the use of a pretested structured questionnaire prepared by reviewing prior studies and other materials on the topic. The questionnaire was translated into Amharic and back into English to ensure its consistency. The interviews were conducted by five nurses who were trained for 2 days by the principal investigator. The interviewers approached the children by introducing themselves, and then collected information after explaining the purpose of their visit by reading the information sheet. Goiter survey method
Study settings and context
The study was conducted in Wolaita Sodo Town, the capital of Wolaita Zone, from December 2010 to February, 2011. Wolaita Zone is one of the 13 zones in the Southern Nations Nationalities and Peoples Region (SNNPR). The altitude of the study area is 1,501 to 3,000 m above sea level and the annual rainfall is 1,695 mm. The common staple foods in the area are cereals, roots, tuber crops, and vegetables. The town has 3 high schools, 10 primary schools, and 19 kindergartens [13, 14]. Study design and populations
A school-based comparative cross-sectional study was conducted in Wolita Zone. The sample populations were schoolchildren in primary school. Following the recommendations of WHO/UNICEF/ICCIDD, schoolchildren of both sexes in the age group from 6 to 12 years were selected because they are highly vulnerable to goiter, easily accessible, and representative of their age group in the community [15]. A total of 534 children, 270 with goiter and 264 without goiter, were selected for the study. Sampling procedure
One primary school was selected out of 10 primary
All students in the recommended age group who were present on the days of survey were clinically examined for enlargement of the thyroid (goiter). Each child was examined across the entire study by three trained health officers, using the palpation method according to recommendations, to ensure staging and to minimize interindividual variability. Goiter grading was done according to WHO/UNICEF/ICCIDD criteria: grade 0, no goiter; grade 1, thyroid palpable but not visible; grade 2, thyroid visible with neck in normal position [15]. In this study, we defined “goiter” as a thyroid gland that had lateral lobes with a volume greater than the terminal phalanges of the palpating examiner, and “endemic goiter” as goiter prevalence greater than 5% within a population. Data quality management
Data quality assurance was in place during data collection and entry. The questionnaire was objective based, logically sequenced, nonleading, and pretested. The data collectors and supervisors were provided with intensive training on the objectives of the study and on areas like thyroid examination to minimize interindividual variability. The collected data were checked by the principal investigator on a daily basis for any incompleteness and/or consistency and necessary corrections were made.
22
E. Wolka et al.
Statistical analysis
Data were entered with the use of EpiInfo, version 3.5.1, and exported to SPSS for analysis. Univariate analysis was used to describe the data according to some important characteristics of study subjects with means, medians, and percentages. Chi-square tests were performed to find the significant variables. Multivariate logistic regression analysis was performed to determine the effect of independent variables on the outcome variable. The data were summarized in percentages and tables. The dependent variable was risk factor for goiter. The independent variables were age, sex, socioeconomic status of parents, and consumption of common staple foods. Ethical considerations
Ethical clearance was obtained from the Institutional
Review Board of the College of Health Science, Addis Ababa University. A letter of permission was obtained from the Sodo Town Health and Education offices. Because of the difficulty of meeting the students’ families, the investigator discussed the ethical issues with the school officials. The study would cause no harm to the students, their families, or the school environment. Therefore, the involvement of the parents was not considered as a prerequisite in this study. Oral informed consent was obtained from the study participants aged 10–12 years. For children younger than 10 years, verbal consent was given. The freedom of children to participate or not participate in the study was explained and respected. Any child diagnosed with goiter during data collection was advised to visit the nearby health facility to obtain possible advice and management; health workers provided counseling and management as needed.
TABLE 1. Sociodemographic profile of children in Ligaba Beyene Elementary School, Sodo Town, Southern Ethiopia, March 2011 With goiter —no. (%)
Without goiter —no. (%)
Total —no. (%)
Sex Male Female
122 (45.2) 148 (54.8)
123 (46.6) 141 (53.4)
245 (45.8) 289 (54.2)
Age (yr) 6–9 10–12
27 (9.9) 243 (90.1)
29 (11) 235 (91)
56 (10.5) 478 (89.5)
Variable
Grade 2 3 4 5 6
p-value .74
.71
.94 26 (9.6) 34 (12.6) 47 (17.4) 93 (34.4) 70 (25.9)
28 (10.6) 37 (14.0) 45 (17.0) 83 (31.4) 71 (26.9)
54 (10.1) 71 (13.3) 92 (17.2) 176 (33.0) 141 (26.4)
Place of birth Wolaita Gamo Gofa Other
243 (90) 13 (4.8) 14 (5.2)
232 (87.9) 11 (4.2) 21 (8.0)
475 (89.0) 24 (4.5) 35 (6.5)
.41
Ethnicity Wolaita Amhara Guraghe Other
220 (81.5) 30 (11.1) 15 (5.6) 5 (1.9)
223 (84.5) 18 (6.8) 17 (6.4) 6 (2.3)
443 (83.0) 48 (9.0) 32 (6.0) 11 (2.0)
Religion Protestant Apostolic Orthodox Muslim Catholic
140 (51.9) 12 (4.4) 99 (36.7) 14 (5.2) 5 (1.9)
138 (52.3) 12 (4.5) 94 (35.6) 16 (6.1) 4 (1.5)
278 (52.0) 24 (4.5) 193 (36.1) 30 (5.6) 9 (1.7)
Total
270 (50.6)
264 (49.4)
534 (100.0)
.36
.98
23
Risk factors for goiter in Ethiopia
Results
goiter and 81 (31.4%) without goiter—were from the fifth grade (table 1).
Sociodemographic characteristics of the children
The study included 534 participants (270 children with goiter and 264 without goiter), for a response rate of 98.9%. All the participants were from Ligaba Beyene Elementary School. The distribution of study subjects by selected sociodemographic characteristics is presented in table 1. Children with goiter and those without goiter were comparable in basic sociodemographic variables except for paternal occupation, which was statistically significantly different between those with and those without goiter. The mean ± SD age of respondents with goiter and without goiter was 11.0 ± 1.1 and 10.9 ± 1.2 years, respectively. The participants were from the second to the sixth grades; the largest number—176, including 93 (34.4%) with
Sociodemographic characteristics of the parents
Thirty-two children with goiter (11.9%) and 25 children without goiter (9.5%) had an illiterate father; 53 children with goiter (19.6%) and 39 children without goiter (14.8%) had an illiterate mother. The mothers of 134 children with goiter (49.6%) and 128 children without goiter (48.5%) were housewives (table 2). Two hundred twenty-three children with goiter (82.6%) and 236 children without goiter (89.4%) had access to tap water. Two hundred twentyseven children with goiter (84.1%) and 196 children without goiter (74.2%) reported commonly consuming goitrogenic foods such as cabbage and cassava (table 3).
TABLE 2. Sociodemographic profile of parents or guardians of children in Ligaba Beyene Elementary School, Sodo Town, Southern Ethiopia, March 2011 With goiter —no. (%)
Without goiter —no. (%)
Total —no. (%)
Father’s educational level Illiterate Literate Primary school Secondary school College or university
32 (11.9) 5 (1.9) 54 (20.0) 87 (32.2) 92 (34.1)
25 (9.5) 5 (1.9) 65 (24.6) 99 (37.5) 70 (26.5)
57 (10.7) 10 (1.9) 119 (22.3) 186 (34.8) 162 (30.3)
Mother’s educational level Illiterate Literate Primary school Secondary school College or university
53 (19.6) 9 (3.3) 104 (38.5) 77 (27.5) 27 (10.0)
39 (14.8) 14 (5.3) 105 (39.8) 72 (27.3) 34 (12.9)
92 (17.2) 23 (4.3) 209 (39.1) 149 (27.9) 61 (11.4)
26 (9.6) 15 (5.6) 76 (28.1) 94 (34.8) 45 (16.7)
14 (5.3) 17 (6.4) 81 (30.7) 83 (31.4) 60 (22.7)
40 (7.5) 32 (6.0) 157 (29.4) 177 (33.1) 105 (19.7)
14 (5.2)
9 (3.4)
23 (4.3)
134 (49.6) 72 (26.7) 28 (10.4) 18 (6.7)
128 (48.5) 64 (24.2) 30 (11.4) 24 (9.1)
262 (49.0) 136 (25.4) 58 (10.8) 42 (7.8)
8 (3.0) 10 (3.7)
12 (4.6) 6 (2.3)
20 (3.7) 16 (3.0)
270 (50.6)
264 (49.4)
534 (100)
Variable
Father’s occupation Teacher Farmer Merchant Other government employee Private or nongovernmental organization Other Mother’s occupation Housewife Merchant Other government employee Private or nongovernmental organization Daily laborer Other Total * p < .05.
p-value .23
.83
.01*
.62
24
E. Wolka et al.
Factors associated with goiter
Some key variables were compared in children with goiter and those without goiter. The results of bivariate logistic regression analysis showed that drinking water from the river was positively and significantly associated with the presence of goiter (crude OR, 2.2; 95% CI, 1.1 to 4.3) as compared with using tap water. Children who consumed common goitrogens such as cabbage and cassava had higher odds of developing goiter (crude OR, 1.8; 95% CI, 1.1 to 2.8). Other variables (age, sex, place of birth, and educational status of father and mother) were found to have no significant association with goiter in the bivariate analysis. Variables that
were identified as having significant association (at a significance level of .05) with goiter in the bivariate regression model were entered into stepwise forward multivariable logistic regression. In the multivariable logistic regression model, consuming common goitrogenic foods such as cabbage and cassava (adjusted OR, 1.9; 95% CI, 1.2 to 2.9) and drinking water from the river (adjusted OR, 2.5; 95% CI, 1.2 to 4.9) were independently associated with goiter (table 4).
Discussion According to a situational analysis carried out by the
TABLE 3. Socioeconomic status, environmental factors, and living arrangements of children and their parents or guardians in Ligaba Beyene Elementary School, Sodo Town, Southern Ethiopia, March 2011 Variable
With goiter —no. (%)
Without goiter —no. (%)
Total —no. (%)
Availability of radio Yes No
218 (80.7) 52 (19.3)
215 (81.4) 49 (18.6)
433 (81.1) 101 (18.9)
Availability of television Yes No
188 (69.6) 82 (30.4)
184 (69.7) 80 (30.3)
372 (69.7) 162 (30.3)
Home ownership Own Rent
181 (67.0) 89 (33.0)
189 (71.6) 75 (28.4)
370 (69.3) 164 (30.7)
Family size ≤5 >5
133 (49.3) 137 (50.7)
143 (54.2) 121 (45.8)
276 (51.7) 258 (48.3)
223 (82.6) 11 (4.1)
236 (89.4) 5 (1.9)
459 (86.0) 16 (3.0)
6 (2.2) 30 (11.1)
9 (3.4) 14 (5.3)
15 (2.8) 44 (8.2)
227 (84.1)
196 (74.2)
423 (79.2)
43 (15.9)
68 (25.8)
111 (20.8)
Water source Tap Public tap water (known as “Bono”) River Well Common food Goitrogenic (cabbage, cassava) Nongoitrogenic
.83
.98
.25
.25
.03*
< .01**
Home comfortable for studying Yes No
247 (91.5) 23 (8.5)
253 (95.8) 11 (4.2)
500 (93.6) 34 (6.4)
Preferred place to study Home School Open field
166 (61.5) 92 (34.1) 12 (4.4)
167 (63.3) 90 (34.1) 7 (2.7)
333 (62.4) 182 (34.1) 19 (3.5)
Total
270 (50.6)
264 (49.4)
534 (100.0)
*p < .05, **p
Eskinder Wolka, Solomon Shiferaw, and Sibhatu Biadgilign Abstract Background. Iodine-deficiency disorders are a major public health problem all over the world. Goiter is the most visible manifestation of iodine-deficiency disorder. Goiter rate is useful to assess the long-term impact of iodine-deficiency disorders. Objective. To determine the risk factors for goiter in primary schoolchildren in southern Ethiopia. Methods. A cross-sectional study on a sample population of 270 children 6 to 12 years of age with goiter and 264 without goiter was conducted in a primary school in Sodo Town, southern Ethiopia. All students in each class were examined for the presence of goiter and classified based on World Health Organization criteria. For each child with goiter, the next child without goiter was selected from the same class. Multivariate logistic regression analysis was employed to determine the effect of independent variables on the goiter rate. Results. A total of 534 participants (270 children with goiter and 264 without goiter) were included. Although the difference was not significant, the prevalence of goiter was higher among girls than among boys (54.8% vs. 45.2%), and the prevalence in both sexes increased with age. In the multivariate logistic regression model, consuming common goitrogenic foods (adjusted OR, 1.9; 95% CI, 1.2 to 2.9) and drinking water from the river (adjusted OR, 2.5; 95% CI, 1.2 to 4.9) were independently associated with goiter. Eskinder Wolka is affiliated with the Department of Public Health, College of Medical and Health Science, Wolaita Sodo University, Wolaita Sodo, Ethiopia; Solomon Shiferaw is affiliated with the School of Public Health, College of Health Sciences, Addis Ababa University, Addis Ababa, Ethiopia; Sibhatu Biadgilign is affiliated with the Department of Epidemiology and Biostatistics, College of Public Health and Medical Science, Jimma University, Jimma, Ethiopia. Please direct queries to the corresponding author: Sibhatu Biadgilign, Department of Epidemiology and Biostatistics, College of Public Health and Medical Science, Jimma University, PO Box 24414, Addis Ababa, Ethiopia; e-mail: [email protected].
20
Conclusions. Goiter rate is significantly associated with consumption of goitrogenic food items in the area and contaminated drinking water. Creating awareness in the community about the consumption of food items and provision of tap water by concerned bodies in the area is recommended to prevent iodine-deficiency disorders.
Key words: Children, Ethiopia, goiter, risk, school Introduction Iodine is an important micronutrient required for human nutrition. Iodine deficiency disorders are a major public health problem all over the world. The effects of iodine-deficiency disorders vary according to nutritional status. Among children, some of the major effects are impaired mental and physical development, mental retardation, physical deformities, and cretinism [1]. Overall, iodine deficiency affects the socioeconomic development of a community [2]. Iodine deficiency is estimated to cause 1.8 million disabilityadjusted life years (DALYs) lost in children younger than 5 years in the 36 focus countries [3]. Iodine deficiency affects an estimated 60 million school-age children in the developing world and is associated with lower test scores and cognitive abilities. Studies indicate that between 35% and 70% of schoolchildren in developing countries may be iodine deficient [4]. In a survey conducted among schoolchildren and household members in Ethiopia, the national goiter prevalence rate ranged from 0.4% to 66.3%, with a mean value of 35% [5, 6]. The prevalence of iodinedeficiency disorders among schoolchildren was 53.3%. The prevalence was higher in girls (56.1%) than in boys (50.8%) [7]. Goiter prevalence in four regional states of Ethiopia—Southern Nation Nationalities and People Region (SNNPR) (the area of the present study), Oromia, Benshangul-Gumuz, and Tigray—was greater than 30%, indicating severe iodine deficiency. According to the third (2007) edition of WHO/UNICEF/
Food and Nutrition Bulletin, vol. 35, no. 1 © 2014, The Nevin Scrimshaw International Nutrition Foundation.
21
Risk factors for goiter in Ethiopia
ICCIDD [8], iodine-deficiency disorders are a major public health problem in Ethiopia. Even though inadequate intake of iodine is the principal cause of iodine-deficiency disorders, goitrogens such as cassava, millet, soybean, bamboo shoot, turnip, and kale, which interfere with the metabolism of iodine and the formation of thyroid hormone, are also implicated [1, 2, 6, 9]. Contamination of drinking water by microbes and other associated nutritional deficiencies, such as vitamin A deficiency, protein–energy malnutrition, and iron-deficiency anemia, are among the environmental and nutritional factors that contribute to the occurrence of iodine-deficiency disorders [10]. Goiter is the most visible manifestation of iodine-deficiency disorders. Goiter rate is useful to assess the long-term impact of iodine-deficiency disorders [11]. Risk factors for goiter are those that do not seem to be a direct cause of the disease, but seem to be associated in some way. Having a risk factor for goiter makes the chances of getting the condition higher, but does not always lead to goiter [12]. The main objective of this study was to determine the risk factors for goiter in primary schoolchildren in southern Ethiopia.
Materials and methods
schools from the town by a purposive sampling technique, considering the large numbers of students needed to get the desired sample size. The number of students and a list of students were obtained from the school. All students in each class were examined for the presence of goiter and classified based on World Health Organization (WHO) criteria until the required sample size was reached. Children who had goiter were given identification numbers. For each child with goiter, the next nearest child without goiter was selected from the same class for comparison, irrespective of the sex of the child. Measurements
Data were collected with the use of a pretested structured questionnaire prepared by reviewing prior studies and other materials on the topic. The questionnaire was translated into Amharic and back into English to ensure its consistency. The interviews were conducted by five nurses who were trained for 2 days by the principal investigator. The interviewers approached the children by introducing themselves, and then collected information after explaining the purpose of their visit by reading the information sheet. Goiter survey method
Study settings and context
The study was conducted in Wolaita Sodo Town, the capital of Wolaita Zone, from December 2010 to February, 2011. Wolaita Zone is one of the 13 zones in the Southern Nations Nationalities and Peoples Region (SNNPR). The altitude of the study area is 1,501 to 3,000 m above sea level and the annual rainfall is 1,695 mm. The common staple foods in the area are cereals, roots, tuber crops, and vegetables. The town has 3 high schools, 10 primary schools, and 19 kindergartens [13, 14]. Study design and populations
A school-based comparative cross-sectional study was conducted in Wolita Zone. The sample populations were schoolchildren in primary school. Following the recommendations of WHO/UNICEF/ICCIDD, schoolchildren of both sexes in the age group from 6 to 12 years were selected because they are highly vulnerable to goiter, easily accessible, and representative of their age group in the community [15]. A total of 534 children, 270 with goiter and 264 without goiter, were selected for the study. Sampling procedure
One primary school was selected out of 10 primary
All students in the recommended age group who were present on the days of survey were clinically examined for enlargement of the thyroid (goiter). Each child was examined across the entire study by three trained health officers, using the palpation method according to recommendations, to ensure staging and to minimize interindividual variability. Goiter grading was done according to WHO/UNICEF/ICCIDD criteria: grade 0, no goiter; grade 1, thyroid palpable but not visible; grade 2, thyroid visible with neck in normal position [15]. In this study, we defined “goiter” as a thyroid gland that had lateral lobes with a volume greater than the terminal phalanges of the palpating examiner, and “endemic goiter” as goiter prevalence greater than 5% within a population. Data quality management
Data quality assurance was in place during data collection and entry. The questionnaire was objective based, logically sequenced, nonleading, and pretested. The data collectors and supervisors were provided with intensive training on the objectives of the study and on areas like thyroid examination to minimize interindividual variability. The collected data were checked by the principal investigator on a daily basis for any incompleteness and/or consistency and necessary corrections were made.
22
E. Wolka et al.
Statistical analysis
Data were entered with the use of EpiInfo, version 3.5.1, and exported to SPSS for analysis. Univariate analysis was used to describe the data according to some important characteristics of study subjects with means, medians, and percentages. Chi-square tests were performed to find the significant variables. Multivariate logistic regression analysis was performed to determine the effect of independent variables on the outcome variable. The data were summarized in percentages and tables. The dependent variable was risk factor for goiter. The independent variables were age, sex, socioeconomic status of parents, and consumption of common staple foods. Ethical considerations
Ethical clearance was obtained from the Institutional
Review Board of the College of Health Science, Addis Ababa University. A letter of permission was obtained from the Sodo Town Health and Education offices. Because of the difficulty of meeting the students’ families, the investigator discussed the ethical issues with the school officials. The study would cause no harm to the students, their families, or the school environment. Therefore, the involvement of the parents was not considered as a prerequisite in this study. Oral informed consent was obtained from the study participants aged 10–12 years. For children younger than 10 years, verbal consent was given. The freedom of children to participate or not participate in the study was explained and respected. Any child diagnosed with goiter during data collection was advised to visit the nearby health facility to obtain possible advice and management; health workers provided counseling and management as needed.
TABLE 1. Sociodemographic profile of children in Ligaba Beyene Elementary School, Sodo Town, Southern Ethiopia, March 2011 With goiter —no. (%)
Without goiter —no. (%)
Total —no. (%)
Sex Male Female
122 (45.2) 148 (54.8)
123 (46.6) 141 (53.4)
245 (45.8) 289 (54.2)
Age (yr) 6–9 10–12
27 (9.9) 243 (90.1)
29 (11) 235 (91)
56 (10.5) 478 (89.5)
Variable
Grade 2 3 4 5 6
p-value .74
.71
.94 26 (9.6) 34 (12.6) 47 (17.4) 93 (34.4) 70 (25.9)
28 (10.6) 37 (14.0) 45 (17.0) 83 (31.4) 71 (26.9)
54 (10.1) 71 (13.3) 92 (17.2) 176 (33.0) 141 (26.4)
Place of birth Wolaita Gamo Gofa Other
243 (90) 13 (4.8) 14 (5.2)
232 (87.9) 11 (4.2) 21 (8.0)
475 (89.0) 24 (4.5) 35 (6.5)
.41
Ethnicity Wolaita Amhara Guraghe Other
220 (81.5) 30 (11.1) 15 (5.6) 5 (1.9)
223 (84.5) 18 (6.8) 17 (6.4) 6 (2.3)
443 (83.0) 48 (9.0) 32 (6.0) 11 (2.0)
Religion Protestant Apostolic Orthodox Muslim Catholic
140 (51.9) 12 (4.4) 99 (36.7) 14 (5.2) 5 (1.9)
138 (52.3) 12 (4.5) 94 (35.6) 16 (6.1) 4 (1.5)
278 (52.0) 24 (4.5) 193 (36.1) 30 (5.6) 9 (1.7)
Total
270 (50.6)
264 (49.4)
534 (100.0)
.36
.98
23
Risk factors for goiter in Ethiopia
Results
goiter and 81 (31.4%) without goiter—were from the fifth grade (table 1).
Sociodemographic characteristics of the children
The study included 534 participants (270 children with goiter and 264 without goiter), for a response rate of 98.9%. All the participants were from Ligaba Beyene Elementary School. The distribution of study subjects by selected sociodemographic characteristics is presented in table 1. Children with goiter and those without goiter were comparable in basic sociodemographic variables except for paternal occupation, which was statistically significantly different between those with and those without goiter. The mean ± SD age of respondents with goiter and without goiter was 11.0 ± 1.1 and 10.9 ± 1.2 years, respectively. The participants were from the second to the sixth grades; the largest number—176, including 93 (34.4%) with
Sociodemographic characteristics of the parents
Thirty-two children with goiter (11.9%) and 25 children without goiter (9.5%) had an illiterate father; 53 children with goiter (19.6%) and 39 children without goiter (14.8%) had an illiterate mother. The mothers of 134 children with goiter (49.6%) and 128 children without goiter (48.5%) were housewives (table 2). Two hundred twenty-three children with goiter (82.6%) and 236 children without goiter (89.4%) had access to tap water. Two hundred twentyseven children with goiter (84.1%) and 196 children without goiter (74.2%) reported commonly consuming goitrogenic foods such as cabbage and cassava (table 3).
TABLE 2. Sociodemographic profile of parents or guardians of children in Ligaba Beyene Elementary School, Sodo Town, Southern Ethiopia, March 2011 With goiter —no. (%)
Without goiter —no. (%)
Total —no. (%)
Father’s educational level Illiterate Literate Primary school Secondary school College or university
32 (11.9) 5 (1.9) 54 (20.0) 87 (32.2) 92 (34.1)
25 (9.5) 5 (1.9) 65 (24.6) 99 (37.5) 70 (26.5)
57 (10.7) 10 (1.9) 119 (22.3) 186 (34.8) 162 (30.3)
Mother’s educational level Illiterate Literate Primary school Secondary school College or university
53 (19.6) 9 (3.3) 104 (38.5) 77 (27.5) 27 (10.0)
39 (14.8) 14 (5.3) 105 (39.8) 72 (27.3) 34 (12.9)
92 (17.2) 23 (4.3) 209 (39.1) 149 (27.9) 61 (11.4)
26 (9.6) 15 (5.6) 76 (28.1) 94 (34.8) 45 (16.7)
14 (5.3) 17 (6.4) 81 (30.7) 83 (31.4) 60 (22.7)
40 (7.5) 32 (6.0) 157 (29.4) 177 (33.1) 105 (19.7)
14 (5.2)
9 (3.4)
23 (4.3)
134 (49.6) 72 (26.7) 28 (10.4) 18 (6.7)
128 (48.5) 64 (24.2) 30 (11.4) 24 (9.1)
262 (49.0) 136 (25.4) 58 (10.8) 42 (7.8)
8 (3.0) 10 (3.7)
12 (4.6) 6 (2.3)
20 (3.7) 16 (3.0)
270 (50.6)
264 (49.4)
534 (100)
Variable
Father’s occupation Teacher Farmer Merchant Other government employee Private or nongovernmental organization Other Mother’s occupation Housewife Merchant Other government employee Private or nongovernmental organization Daily laborer Other Total * p < .05.
p-value .23
.83
.01*
.62
24
E. Wolka et al.
Factors associated with goiter
Some key variables were compared in children with goiter and those without goiter. The results of bivariate logistic regression analysis showed that drinking water from the river was positively and significantly associated with the presence of goiter (crude OR, 2.2; 95% CI, 1.1 to 4.3) as compared with using tap water. Children who consumed common goitrogens such as cabbage and cassava had higher odds of developing goiter (crude OR, 1.8; 95% CI, 1.1 to 2.8). Other variables (age, sex, place of birth, and educational status of father and mother) were found to have no significant association with goiter in the bivariate analysis. Variables that
were identified as having significant association (at a significance level of .05) with goiter in the bivariate regression model were entered into stepwise forward multivariable logistic regression. In the multivariable logistic regression model, consuming common goitrogenic foods such as cabbage and cassava (adjusted OR, 1.9; 95% CI, 1.2 to 2.9) and drinking water from the river (adjusted OR, 2.5; 95% CI, 1.2 to 4.9) were independently associated with goiter (table 4).
Discussion According to a situational analysis carried out by the
TABLE 3. Socioeconomic status, environmental factors, and living arrangements of children and their parents or guardians in Ligaba Beyene Elementary School, Sodo Town, Southern Ethiopia, March 2011 Variable
With goiter —no. (%)
Without goiter —no. (%)
Total —no. (%)
Availability of radio Yes No
218 (80.7) 52 (19.3)
215 (81.4) 49 (18.6)
433 (81.1) 101 (18.9)
Availability of television Yes No
188 (69.6) 82 (30.4)
184 (69.7) 80 (30.3)
372 (69.7) 162 (30.3)
Home ownership Own Rent
181 (67.0) 89 (33.0)
189 (71.6) 75 (28.4)
370 (69.3) 164 (30.7)
Family size ≤5 >5
133 (49.3) 137 (50.7)
143 (54.2) 121 (45.8)
276 (51.7) 258 (48.3)
223 (82.6) 11 (4.1)
236 (89.4) 5 (1.9)
459 (86.0) 16 (3.0)
6 (2.2) 30 (11.1)
9 (3.4) 14 (5.3)
15 (2.8) 44 (8.2)
227 (84.1)
196 (74.2)
423 (79.2)
43 (15.9)
68 (25.8)
111 (20.8)
Water source Tap Public tap water (known as “Bono”) River Well Common food Goitrogenic (cabbage, cassava) Nongoitrogenic
.83
.98
.25
.25
.03*
< .01**
Home comfortable for studying Yes No
247 (91.5) 23 (8.5)
253 (95.8) 11 (4.2)
500 (93.6) 34 (6.4)
Preferred place to study Home School Open field
166 (61.5) 92 (34.1) 12 (4.4)
167 (63.3) 90 (34.1) 7 (2.7)
333 (62.4) 182 (34.1) 19 (3.5)
Total
270 (50.6)
264 (49.4)
534 (100.0)
*p < .05, **p
