Original Research••

Prevalence of adequately iodised salt and associated factors among households in Gambela district, Southwest Ethiopia: a cross-sectional study

Abstract

Background Iodine deficiency disorders (IDDs) are among the major public health problems for populations worldwide. Although the recommended strategy for the prevention of IDD is universal salt iodisation, little is known about the availability of adequately iodised salt among households in Southwest Ethiopia. Therefore, this study aimed to determine the prevalence of adequately iodised salt and associated factors among households in Gambela district, Southwest Ethiopia.

Methods A community-based cross-sectional study was conducted in July 2019. A multistage sampling method was employed to select 422 households. A structured questionnaire and rapid test kits were used as data collection instruments. Multivariate logistic regression was used to identify associated factors.

Results Approximately 52.8% (95% CI: 47, 57%) of households had adequately iodised salt. Higher educational status (adjusted OR (AOR)=4.27, 95% CI: 1.47, 12.44), favourable attitude toward iodised salt use (AOR=5.69, 95% CI: 2.83, 11.42), walking less than 30 min to buy iodised salt (AOR=4.69, 95% CI: 2.56, 8.60), using packed salt (AOR=2.75, 95% CI: 1.54, 4.93) and using covered salt containers (AOR=3.93, 95% CI: 2.21, 6.98) were factors positively associated with the availability of adequately iodised salt among households.

Conclusions The prevalence of adequately iodised salt among households in Gambela district is very low. Therefore, enhancing community awareness about the benefit and good practice of iodised salt should be emphasised in addition to improving accessibility. Measures to improve the literacy of households also need to be underlined.

What is already known on this topic

  • Universal Salt Iodization (USI) was recommended by the WHO as a safe, cost-effective and sustainable strategy to ensure sufficient intake of iodine by all individuals. In 2011, Ethiopia had passed a comprehensive salt regulation which demanded that all salt for human consumption should be iodised; however, the iodised salt coverage among households in Ethiopia is still below the WHO USI coverage target.

What this study adds

  • The study assessed the prevalence of adequately iodised salt among households in Gambela district and found that the prevalence did not meet what the WHO recommends. The study revealed that availability of adequately iodised salt among households was associated with educational status of respondent, attitude level, walking time taken to buy iodised salt, type of salt used and salt container closure.

How this study might affect research, practice or policy

  • This study will help policymakers and health professionals for the prevention of iodine deficiency disorders.

  • Public authorities should regularly monitor the quality of salt at the household level in the study area, and also the compliance of the regulation of mandatory salt iodination by salt producers.

  • Educating the community about the importance of iodised salt use and the consequences of iodine deficiency is expected to increase the prevalence of adequately iodised salt among households.

  • Informing the public about proper use of iodised salt, such as storing iodised salt in closed containers and using packed salt, is essential.

  • Concerned bodies ought to make sure that iodised salt is accessible to households within 30 min of walking towards shops.

Introduction

The WHO indicated that iodine deficiency disorders (IDDs) are among the major public health problems for populations all over the world.1 Iodine deficiency affects all populations, particularly women and children.2 Every year, approximately 38 million neonates in less developed areas suffer from the lifelong consequences of brain damage associated with IDDs, which affect a child’s ability to learn and productivity in later life.3 In Ethiopia, almost 35% of children are affected by goitres,4 while the prevalence of palpable and visible goitres among pregnant and lactating mothers is 31%.5

The WHO recommends 90 µg, 120 µg, 150 µg and 250 µg daily intake of iodine for preschool children, schoolchildren, adolescents, and pregnant and lactating women, respectively.6 In 1994, Universal Salt Iodization (USI) was recommended by the WHO and UNICEF as a safe, cost-effective and sustainable strategy to ensure sufficient intake of iodine by all individuals.7 However, globally and in sub-Saharan Africa, only 75% and 64% of all households were using iodised salt, respectively.8 9

Ethiopia passed a comprehensive salt regulation in 2011 that commanded that all salt for human consumption in the country should be iodised.10 Despite this attempt, iodised salt coverage among households in Ethiopia is still below the WHO USI target of 90% coverage.7 11 Different studies in Ethiopia showed that the household prevalence of adequately iodised salt, defined as a salt that has iodine greater than or equal to 15 parts per million (PPM), was much lower than the international USI target.12–14

Various studies worldwide have revealed different factors associated with the prevalence of adequately iodised salt among households. Hence, the prevalence of adequacy was associated with socioeconomic status in Bangladesh, India, Indonesia, the Philippines, Senegal and Tanzania.15 Moreover, using a packed salt and knowledge about iodised salt use were determinants of the prevalence of adequately iodised salt among households in a study in Nepal and Pakistan, respectively.16 17 Marital status and access to information were predictors of the prevalence of iodised salt in households in Ghana.18 19 Some studies in Ethiopia reported that using packed salt, access to information, income of households, education, knowledge about iodised salt use, not exposing salt to sunlight, storing salt in dry places and storing salt in containers with lids were among the factors significantly associated with the prevalence of adequately iodised salt among households.20–22

The Ethiopian national survey conducted in the Gambela region did not determine factors associated with the prevalence of adequately iodised salt among households in the district.11 Furthermore, studies conducted on the prevalence of adequately iodised salt among households in Ethiopia had inconsistent findings.23–25 Therefore, this study aimed to determine the prevalence of adequately iodised salt and its determinants among households in Gambela district, Southwest Ethiopia. Eventually, this study will be a big input to health professionals and policymakers for the prevention of IDDs.

Materials and methods

Study design and period

A community-based cross-sectional study was conducted from 1 December 2019 to 31 December 2019.

Study setting

The study was conducted in the Gambela district found in the Gambela region, which is one of the nine ethnic divisions of Ethiopia, located 777 km southwest of Addis Ababa (figure 1).26 According to the 2019 Ethiopian population projection, Gambela region contributes to 0.47% of Ethiopian population.27 In 2019, the district had a total population of 59 462, comprising 12 927 households. Gambela district has five kebeles, which are the smallest administrative units in Ethiopia.

Figure 1
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Figure 1

Map of Gambela region including Gambela district (the study area).

Study population

The source population was all households in Gambela district, while the study population was all selected households found in selected kebeles of the district. A member of a household who is 18 years old and above, mostly involved in cooking food, was interviewed. An individual in a selected household who was sick and unable to respond at the time of data collection was excluded from the study.

Sample size determination

Sample size was calculated using Epi Info V.7 Stat Calc computer software by the following assumptions: two-sided confidence level of 95%, power of 80%, exposed to unexposed ratio 1:1, considering 10% for non-response, the design effect of two and taking magnitude of prevalence of adequately iodised salt at household level among those who place salt at a dry place of 30.40% and 2.13 OR from study done in Robe town.28 Finally, the sample size calculated for this study was 422.

Sampling procedure

A two-step multistage sampling method was employed to select households. Accordingly, in the first stage, three kebeles were selected by chance using a simple random sampling technique. Then, the sample size was allocated proportional to the household size of each kebele. In the second stage, households were randomly selected from the previously selected kebeles by employing systematic random sampling technique using a sampling frame taken from the respective kebele administrators.

Data collection and measurement of variables

The data were collected by using a structured interviewer-administered questionnaire and rapid iodine salt test kit (online supplemental material 1). The questionnaire, which was adapted by taking questions from a lot of relevant literature, was used to collect data regarding the iodine content of salt in a household (outcome variable) and independent variables such as household sociodemographic characteristics, knowledge and attitudes toward iodised salt use and various practices related to the use of iodised salt.12 22 28 The questionnaire was initially prepared in English and then translated into the Amharic language and then back to English by two fluent speakers to check its consistency.

The iodine content of salt in a household was determined by using the rapid iodine test kit at the end of the interview. Determination of the iodine content of iodised salt was performed using standardised procedures recommended by the WHO.7 Accordingly, one drop of starch solution was squeezed onto a half teaspoon sample of table salt obtained in each household. If the colour changed from light blue to dark violet, it was matched to a colour chart provided with the test kit, and the iodine concentration was classified as <15 or ≥15 PPM.

A household declared to have adequately iodised salt when its sampled salt has iodine ≥15 PPM.29 If a participant correctly answers more than 50% of knowledge questions about iodised salt use, then the participant has good knowledge about iodised salt use.30 Favourable attitude toward iodised salt use is defined as correctly answering more than 50% of questions about attitude toward iodised salt use.31

Data quality control

A pretest of the questionnaire was carried out on 21 (5% of the sample size) households in two kebeles not selected for the study. The performance of the rapid test kit was routinely monitored. The expiration date of the rapid test kit was checked before use. Training was given to research assistants on the topic and purpose of the research, on how to approach study subjects and how to use the questionnaire and the rapid test kit. The collected data were checked for completeness, accuracy and clarity by the principal investigator and supervisor. Quality checking was performed on the data collection day and after data collection. Correction was made before the next data collection. Data clean-up and cross-checking were performed before analysis. Multivariate logistic regression analysis was used to control for possible confounding variables. The fitness of multivariate logistic regression was assessed by the Hosmer‒Lemeshow goodness-of-fit test.

Data analysis

The collected data were explored for missing data, and the distribution of outcome variables as well as the test of parallel lines and model fitness information were checked. Data entry and analysis were performed by SPSS (V.20) after data cleaning. Descriptive analysis results were presented using tables and texts. Since the interest was identifying households with adequately iodised salt, the dependent variable was coded as 1 if household sampled salt has iodine ≥15 PPM and coded as 0 if not. The multicollinearity effect was checked, and those variables with no collinear effect were included in the logistic regression analysis. Multivariate logistic regression analysis was employed to identify the predictors of the prevalence of adequately iodised salt among households. The crude OR and adjusted OR (AOR) along with their respective 95% CIs were calculated to measure the strength of the association. The association between the explanatory and dependent variables was assessed at a p value of 0.05.

Patient and public involvement

The patient and/or the public, including health authorities, helped the on-field research activities to run smoothly by approving the study, coordinating the community and the available local health workforce, as well as by participating directly in sampling of the study participants.

Results

Sociodemographic characteristics

A total of 411 households were interviewed, yielding a response rate of 97.4%. The mean (±SD) age of the participants was 28.9 (±9.7) years. The majority (76.9%) of study participants were female, and more than half (61.1%) of respondents’ relationships in the household were mothers. The majority (74.7%) of the study participants lived in male-headed households, and four-fifths (81.0%) of the study participants had a family size less than six (table 1).

Table 1
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Sociodemographic characteristics of respondents (N=411)

Practice of respondents regarding iodised salt

Approximately one-third (36.5%) of the participants reported that they were walking more than 30 min to buy iodised salt, and half (52.1%) of them were buying unpacked salt. Most (71.5%) of the respondents used a container with a cover to store salt at home, while almost one-fourth (28%) of respondents added salt early and in the middle of cooking (table 2).

Table 2
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Practice of respondents regarding iodised salt (N=411)

Prevalence of adequately iodised salt at the household level

This study found that the prevalence of adequately iodised salt (15 PPM or more iodine) among households in Gambela district was 52.8% (95% CI: 47, 57%). One hundred forty (34.06%) respondents had inadequate iodine (less than 15 PPM) in their salt at household, whereas 54 (13.14%) of them did not have any iodine (0 PPM) in their salt.

Factors associated with prevalence of adequately iodised salt among households

Upon multivariate logistic regression, educational status (AOR=4.27, 95% CI: 1.47, 12.44), attitude level (AOR=5.69, 95% CI: 2.83, 11.42), walking time taken to buy iodised salt (AOR=4.69, 95% CI: 2.56, 8.60), type of salt used (AOR=2.75, 95% CI: 1.54, 4.93) and salt container closure (AOR=3.93, 95% CI: 2.21, 6.98) were factors associated with prevalence of adequately iodised salt among households. The multivariate logistic regression model was fitted well according to Hosmer-Lemeshow goodness-of-fit test (p=0.11) (table 3).

Table 3
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Factors associated with prevalence of adequately iodised salt among households (N=411)

Discussion

Since USI is the best strategy for the prevention of IDDs, it is crucial to identify the level of iodine in a household’s salt.1 Accordingly, this study found that the prevalence of adequately iodised salt among households in Gambela district was 52.8% (95% CI: 47, 57%). This finding is lower than the WHO USI target of 90% coverage.7 Nonetheless, the finding was higher compared with studies conducted in Eastern Ethiopia (7.5%), in South Eastern Ethiopia (32.7%) and in Kenya (26.2%).23 28 32 This discrepancy is probably due to the improved effort of the local government to ensure market availability of iodised salt and might also be due to more households in this study area storing salt in a dry place than in the latter studies. Ethiopia has ratified a mandatory salt iodisation regulation which has a good compliance that might be due to support from the WHO’s Nutrition International Programme and strategies like use of centralised iodisation facilities.10 33 34

Higher odds of availability of adequately iodised salt were observed among participants with higher educational status compared with those participants with no formal education. This association was also observed in studies done in Iraq and in Ethiopia.35–37 Perhaps this association might be because a higher educational level increases the probability of awareness of iodised salt use.

Those participants with favourable attitudes toward iodised salt use were more than five times more likely to have adequately iodised salt at the household level than those with unfavourable attitudes, which is in agreement with a study carried out in Bangladesh.38 This might be attributed to the boost in the tendency to buy and consume iodised salt regularly because of having a favourable attitude toward iodised salt use.

This study revealed that participants who can get iodised salt within 30 min of walking were more than four times more likely to have adequately iodised salt than those participants who can get iodised salt after walking more than 30 min. A study conducted in North Ethiopia also showed a similar direction of association to the current study.39 A possible explanation for this could be that obtaining iodised salt in nearby shops, just walking few minutes, decreases transport costs and the difficulty of access, thus increasing iodised salt availability.

Similar to the current study, various studies conducted in Ethiopia and Iraq revealed that using packed salt increases the chance of having adequately iodised salt among households.23 35 40 The association could be due to a reduction in sunlight exposure by packing iodised salt, which eventually reduces iodine loss in the iodised salt among households.30

Households that were storing salt in a covered container were approximately four times more likely to have adequately iodised salt compared with their counterparts. Likewise, a study in Kenya found that households with covered salt containers were more likely to have adequately iodised salt than households without covered salt containers.32 This association might be due to the fact that storing iodised salt in an uncovered container exposes the salt to humidity, moisture and light that lowers the iodine level of the salt.

One of the drawbacks of the study is the use of cross-sectional study design, which does not reflect temporal causal relation between the outcome variable and independent variables. Another limitation of the research is that the iodine level of household’s salt was determined by using rapid testing kit which did not include titration level of iodine in the salt. The study barely identified whether iodine level of household’s salt was affected before or after the household purchased the salt. Future researches are recommended to address the limitations of the current study.

In conclusion, the prevalence of adequately iodised salt among households in Gambela district was much lower than the WHO recommendation, and it was associated with educational status of respondent, attitude level, walking time taken to buy iodised salt, type of salt used and salt container closure. Therefore, public authorities should regularly monitor the quality of salt at the household level in the study area. Moreover, educating the community about the importance of iodised salt use and the consequences of iodine deficiency is expected to increase the prevalence of adequately iodised salt among households. Furthermore, informing the public about proper use of iodised salt, such as storing iodised salt in closed containers and using packed salt, is essential. Concerned bodies ought to make sure that iodised salt is accessible to households within 30 min of walking towards a nearby shop.

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