Background
Iodine status surveys of women in Somaliland present widely conflicting results. Previous research indicates elevated concentrations of iodine (IQR 18–72 µg/L) in groundwater used for drinking and cooking, but the relationship with iodine intake is not characterized well.
Objective
We aimed to investigate the contribution of household water iodine concentration (WIC), breastfeeding, total fluid intake, hydration levels, and urine volume on urinary iodine concentration and excretion (UIC, UIE) during 24 hours, and to define iodine status from iodine intake estimates and median UIC, normalized to a mean urine volume of 1.38L/day (hydration-adjusted).
Methods
The study sample comprised 118 nonpregnant, healthy women aged 15–69. All resided in Hargeisa; 27 breastfeeding. Data collection consisted of a 24-hour (24-h) urine collection, a 24-h fluid intake diary, a beverage frequency questionnaire, and a structured recall interview. We measured UIC and WIC in all urine and in 49 household-water samples using the Sandell–Kolthoff reaction.
Results
WIC ranged between 3 and 188 μg/L, with significant median differences across the water sources and city districts (P < 0.003). Non-breastfeeding women were borderline iodine sufficient (hydration-adjusted mUIC of 109 [95% CI, 97–121] μg/L), whereas breastfeeding women showed a mild iodine deficiency (73 [95% CI, 54–90] μg/L). There were strong correlations (rho 0.50–0.69, P = 0.001) between WIC and UIC, with iodine from household water contributing more than half of total iodine intake. Multivariate regression showed hydration and breastfeeding status to be the main predictors of UIC.
Conclusions
Iodine from household water is the main contributor to total iodine intake among women in Hargeisa, Somaliland. Variation in female hydration and spatial and temporal WIC may explain diverging mUIC between studies. Water sources at the extremes of low and high iodine concentration increase the risk of subpopulations with insufficient or more than adequate iodine intake.