Iodine status and cognitive function of women and their five year-old children in rural Sidama, southern Ethiopia.

OBJECTIVE: Iodine deficiency is one of the most common micronutrient deficiencies worldwide and is a major cause of preventable mental retardation. The purpose of this study was to assess the iodine status and cognitive function of women of childbearing age and their five-year-old children.
METHOD: A cross-sectional study was conducted in a rural village in southern Ethiopia. A convenience sample of one hundred women and their five year-old children participated in the study. Goiter grade, urinary iodine excretion, Raven's CPM and cognitive tests from the Kaufman ABC-II, were administered to the women and their children.
RESULTS: The use of iodized salt was only 2%. The mean iodine content of water in and around the study area was 4.46 microg/l. Occurrence of goiter was 85% in the women and 33% in children. Urinary iodine excretion for all participants was <49 microg/L, the top of the range for moderate iodine deficiency. The median urinary iodine excretion (UIE) was 1 microg/L for both mothers and children. For children, measures of short term memory (Sequential index) were correlated with the visual processing (Simultaneous index) (r = 0.49, p < 0.0001). Goiter and urinary iodine excretion were correlated to Sequential index (r = 0.39, p = 0.0011 and r = 0.2, p = 0.05) respectively, but not to the Simultaneous index for children. Sequential (r = 0.21, p = 0.03) and Simultaneous (r = 0.29, p = 0.004) indices of mothers and children were correlated.
CONCLUSION: The high prevalence of goiter and the low urinary iodine excretion demonstrate serious long- and short-term iodine deficiency in the study area. Relations between measures of iodine status and short term memory in children raise concern about potential functional effects of iodine deficiency.