Availability of adequately iodized salt at household level in Dessie and Combolcha Towns, South Wollo, Ethiopia

Iodine is an essential element for normal function of the thyroid gland. Its deficiency is the most common cause of preventable mental retardation and brain damage in the world [1–3]. Iodine deficiency disorders (IDD) is manifested in multiple adverse health consequences like decreased child survival rates, goitre, abortion, stillbirth, malformation and overall impaired growth and development [1, 4, 5] and remained major public health challenge and an obstacle to economic development worldwide [6, 7]. Iodine deficiency remains a public-health problem in many low-income countries, and more than a billion individuals consumed an insufficient dietary iodine [8]. Reports revealed that 38 million children born every year are at risk of brain damage because of iodine deficiency [9].

In Ethiopia, around 28 million people suffer from goitre, and more than 35 million people are at risk of iodine deficiency. More importantly, 50,000 perinatal deaths are related to iodine deficiency each year in Ethiopia. The education potential of the nation is unattained as iodine deficiency may cause an intelligence quotient reduction of 13.5 points [9]. The problem is both a threat to the productivity of the workforce and a cause of cretinism and mental retardation which lead to an enormous loss of gross domestic product [10].

WHO recommends a daily intake of 90 μg of iodine for preschool children, 120 μg for schoolchildren, 150 μg for adolescents and adults, and 200 μg for pregnant and lactating women [11]. WHO recommended Universal Salt Iodization (USI) for elimination of IDDs [11] a daily intake of salt by all members of the population should provide the required amount of iodine [12].

Salt iodine testing is an important process indicator for monitoring progress towards Universal Salt Iodization (USI) [13]. WHO/UNICEF/ICCIDD recommends that the salt iodine content at the packaging level must be 50–60 ppm and 20–30 ppm at the retail shops, to achieve at least 15 ppm in the household dietary consumption [2]. The salt iodine content is estimated by rapid test kit(RTK) methods which measures of the iodine content [11].

Iodization of salt is currently carried out following the USI initiative [14, 15]. The concentration of iodine from iodized salt can be influenced by the variability of iodine during iodization process, packing with bags and instability of iodine in the salt. Moreover, moisture content of salt, humidity, light, heat, impurities in salt, alkalinity or acidity, and the form in which the iodine is present, affect iodine stability in salt [16].

Recent monitoring of the iodine indicated that 62% of households used adequately iodized salt containing at least 15 ppm iodine in Laelay Maychew District, Northern Ethiopia and South Africa [17–19], considerably below the international goal of 90% coverage [11].

According to the Ethiopia Demography and Health Survey 2016, 89% of the Ethiopian population uses iodized salt [20]. Measuring iodine concentrations and documentation of losses at the consumers’ level are essential elements of a programme to eliminate iodine deficiencies. Additionally, it is important to monitor what percentage of the population remains at risk of insufficient intake of iodine. Therefore, this study aimed to investigate the adequacy of iodine from dietary salt at household level.

The study found that the overall percentage of households who used inadequate iodized salt (< 15 ppm)was 31.2%. The iodized salt inadequacy was more severe in Combolcha residents. The finding of this study revealed that adequacy of iodized salt was much higher than reports from rural community of Maychew (33%) [21], West Ethiopia (8.7%) [22] and Gondar town, Ethiopia (28.9%) [23] and Asella Town, Ethiopia (62.9%) [24]; and similar result was observed from urban area of Sidama Zone, Ethiopia (65%) [25]. Even though there are many variation and strategies across countries, the finding of the study was also higher as compared to findings from other low income contries [13, 26]. In contrast to the above finding, adequacy of iodized salt in the study was lower than findings from EasternNepal (82.6%) [27] and Telangana, India (79%) [3].

The reason for these variations may be due to relatively wide time elapsed between the current study and others. Additionally, controlling of iodine deficiency disorders has been given universal attention with strong monitoring and evaluation of iodine from dietary salt at every levels (at production, transportation and consumption levels). The differences in agro-ecological situations, socio-economic status and perceived knowledge and practices among households may bring the above discrepancies in different areas.

Proportional Odds model with Logit link function was used to identify predictors of iodized salt adequacy at household level. The model identified place of residence, households in the fourth quintile of socio-economic class, packing and labeling site and exposure for sunlight as having statistical significant association with adequacy of iodized salt at consumption level. The salt samples brought from Dessie household residents were found to be more likely adequately iodized as compared to salt samples from Combolcha Town. This report was in line with the WHO recommendation report [2], finding from studies conducted in West Ethiopia [22], Eastern Nepal [27] and Telangana, India [3] indicated that the level of moisture and humidity of areas affect the content of iodine in the salt. Additional reasons may be most of the households of Combolcha Town used open market salt for cooking and they exposed the salt to sunlight.

Households found in higher socio-economic categories showed more significant observed difference in better adequacy of iodized salt use as compared to households found in low socio-economic status. Many studies agreed that iodized salt was not accessible for most of the poor society in the world. Reports from Asella town [24], Sidama Zone [25] and rural India [26] postulated that the better socio-economic status, the more adequately iodized salt used and agreed that packed iodized salt is not affordable for the poor.

Regarding place of iodized salt where it was packed and labeled; households who used open market salt were less likely to use adequately iodized salt. Study conducted by Kumar A., et al. in Eastern Nepal [27] found that there is a significant association between use of open market salt and inadequacy of iodine content in dietary salt. Similarly studies from West Ethiopia [22], Sidama, SouthernEthiopia [25], Gondar, Ethiopia [23] and Telangana, India [3] stated that the use of packed salt has positive association with increased contents of iodine. Open market salt is more prone to evaporation and iodine by its nature is highly volatile.

This study revealed that the odds of having adequate iodine concentration by households who did not expose for sunlight were about three times higher than the odds of iodized salt used by households who exposed it for sunlight. Studies from Gondar, Ethiopia [23], India [13] and London confirmed that heat can contribute the highest share for iodine loss. Sunlight exposure hastens the oxidation of iodide to elemental iodine and this is highly unstable.

The percentage of adequately iodized salt (68.8%) is not a warranty to conclude that utilization of iodine is sufficient unless we determine urinary iodine concentration of households in the study area. Due to the relatively small sample size and the winter season of data collection period, the finding of the study may not strong enough to represent the general population.

In conclusion, availability of adequately iodized salt in Dessie and Combolcha towns was 68.8%. As compared to the targets of WHO recommendation and the Ethiopian- Federal Ministry of Health, the progress in the study area remaines slow. Only 25% of the households knew the benefit of iodized salt and most of them did not know negative effect of sunlight exposure.

The level of humidity, socio-economic status, use of iodized salt which is packed and did not expose to sunlight had significant association with adequacy of iodized salt. Working at grass root level is vital to achieve the desired target; to internalize the consequences of iodine deficiencies and proper utilization of iodized salt by enhancing the knowledge of individuals about the role of iodine and benefit of iodized salt. There should be periodical monitoring and evaluation of iodine particularly in areas where the use of open salt is common. Educating the households regarding proper practices of iodized salt use should be extensively addressed like not to expose for heat, adding salt at the end of cooking, placing in dry place and proper storage of salt in the house. There should be also regular and strick monitoring schedule at household level to take an immediate action.