Objective: To compare the iodine status of pregnant women and their children who were sharing all meals in Bangalore, India.
Design: A cross-sectional study evaluating demographic characteristics, household salt iodine concentration and salt usage patterns, urinary iodine concentrations (UIC) in women and children, and maternal thyroid volume (ultrasound).
Setting: Antenatal clinic of an urban tertiary-care hospital, which serves a low-income population.
Subjects: Healthy pregnant women in all trimesters, aged 18-35 years, who had healthy children aged 3-15 years.
Results: Median (range) iodine concentrations of household powdered and crystal salt were 55·9 (17·2-65·9) ppm and 18·9 (2·2-68·2) ppm, respectively. The contribution of iodine-containing supplements and multi-micronutrient powders to iodine intake in the families was negligible. Adequately iodized salt, together with small amounts of iodine in local foods, were providing adequate iodine during pregnancy: (i) the overall median (range) UIC in women was 172 (5-1024) µg/l; (ii) the median UIC was >150 µg/l in all trimesters; and (iii) thyroid size was not significantly different across trimesters. At the same time, the median (range) UIC in children was 220 (10-782) µg/l, indicating more-than-adequate iodine intake at this age. Median UIC was significantly higher in children than in their mothers (P=0·008).
Conclusions: In this selected urban population of southern India, the iodized salt programme provides adequate iodine to women throughout pregnancy, at the expense of higher iodine intake in their children. Thus we suggest that the current cut-off for median UIC in children indicating more-than-adequate intake, recommended by the WHO/UNICEF/International Council for the Control of Iodine Deficiency Disorders may, need to be reconsidered.
Keywords: Children; India; Iodine; Iodized salt; Pregnant women; Urinary iodine concentration.