Abstract
The Somali population in the horn of Africa is one of the hardest affected by civil war, social unrest, draught and displacement in the African continent. Morbidity, age-specific mortality and malnutrition ratios are high and food diversity low. The first national Somali micronutrient survey (2009) unexpectedly found “more than adequate” or “excessive” intake of iodine amongst women and children despite negligible usage of fish and iodized salt.
This study’s objective was to investigate how hydration status could affect estimates of iodine intake in non-pregnant women 15-69 years and to quantify the contribution of iodine intake from local water sources in this sub-population. Non-breastfeeding and breastfeeding women were the two main target-groups, the latter typically considered more susceptible for iodine deficiency.
A two stage, clustered, probability proportionate to size sampling with elements of purposeful re-sampling was applied to a cross-sectional study of women recruited through local nongovernmental organizations across Hargeisa city. Demographic and anthropometric data were obtained through three structured interviews and measurements. Urine was collected over 24 hours, drinking water taken from homes and the iodine concentration in both fluids measured. A drinking and voiding diary from the same 24 hours provided additional data of fluid metabolism.
Out of 160 women, 127 completed the whole study. 118 women were included in all analysis, 27 of which were breastfeeding. Demographic and SES characteristics of the women were close to a sample of urban Somaliland women from the MICS-3 study. Mean adjusted urine volume over 24 hours was 1.28 litres. There were high correlation between urine volume and recorded urine units voided (r = .873) and urine colour (rs = -.819). A median UIC of 125 μg/l was found. In the subsample of breastfeeding women, the result was 73 μg/l; indicating risk of mild iodine deficiency. Mean drinking volume over the same 24 hours was 2.04 litres. An independent drinking frequency questionnaire estimated a mean of 8.1 drink-servings per day. 90% of all fluids drunken came from local water sources. Public tap water and water from tanker trucks provided 95% of all plain water for drinks and food. The mean iodine concentration in 49 water samples, from 4 different main water sources, was 51 μg/l. A threefold difference (p<0.001) between the sources was found. A median iodine intake of 212 μg/d for breastfeeding women and 168 μg/d for non-breastfeeding women were estimated. We calculated proportion of iodine intake from main household water sources to be 55-70% of the total iodine intake in this latter group.
The study showed that the group of women had 10-15% smaller urine production than assumed in the reference material guiding the international recommendations for UIC levels in populations. The study also showed that the majority of iodine consumption originated from the women’s main water sources.
The authors recommend that UIC is being measured in a larger and representative sample of breast-feeding women in Hargeisa and that iodine concentration in main water sources for the city is being controlled in all seasons throughout the year.
National UIC estimates might hide large regional deviations due to different iodine levels from one water source to another. There is a need for better local estimates of iodine status in the Somaliland population.