Iodine intake among children under 5 years of age in Kazakhstan

INTRODUCTION:  Iodine deficiency is a major risk factor for several thyroid disorders. A new Law on mandatory iodization of table and cattle salt was adopted in 2003 year in Kazakhstan. According to the national report from 2011 95.9% of population is supplied by iodized salt. However the results of this intervention remain poorly understood. We assessed iodine intake among children <5 years of age at the national level by studying concentration of urinary iodine excretion (UIE).

METHODS:  Altogether, 1,311 randomly selected children aged 6-59 months from all regions of Kazakhstan were included in a population-based cross-sectional study in 2011. UIE was measured in urine samples and iodine intake was assessed using ammonium persulfate digestion with spectrophotometric detection of the Sandell-Kolthoff reaction in a reference iodine laboratory  at the Kazakh Academy of Nutrition calibrated as a part of the  EQUIP program (CDC, Atlanta). The prevalence of iodine deficiency is presented as proportions with 95% confidence intervals (CI).

RESULTS: The median and mean UIE were 203.9 µg/L and 263.7 µg/L (95%CI: 251.4 – 276.1), respectively, in the full sample. The overall prevalence of iodine deficiency was 21.0% (95% CI: 18.8-23.3) including mild (13.3%, 95% CI: 11.5-15.2), moderate (5.9%, 95% CI: 4.6-7.3) and severe (1.8%, 95% CI: 1.2-2.7). The prevalence of iodine deficiency significantly exceeded the national level in West Kazakhstan (61.3%, 95% CI: 50.6-72.0), Kyzylorda (53.7%, 95% CI: 42.7-64.7), Pavlodar (52.0%, 95% CI: 40.6-63.4), East Kazakhstan (45.8%, 95% CI: 44.9-56.8) and South Kazakhstan (37.1%, 95% CI: 26.3-47.9).

CONCLUSIONS: More than one in five children in the age-group 6-59 months has iodine deficiency with worrisome variations between the regions. Analysis of the situation in each area provides an opportunity to target interventions to secure adequate iodine intake among children in Kazakhstan.