Iodine status in pregnant women living in Melbourne differs by ethnic group

The iodine status of pregnant women from different ethnic groups in an Australian population was determined by measuring urinary iodine concentration (UIC) from stored spot urine samples. Study subjects were selected from pregnant women participating in a Down Syndrome screening study at Monash Medical Centre in Melbourne, Australia. In total, 263 Vietnamese, 262 Indian/Sri Lankan (ISL) and 277 Caucasian women were included. The median UIC of Caucasian women (52 μg/L) was significantly lower than that of both Vietnamese women (58 μg/L, P <0.01) and ISL women (61 μg/L, P = 0.03). The proportion of women who had a UIC below 50μg/L was 48.4% of the Caucasian women, 38.4% of the Vietnamese women and 40.8% of the ISL women. These data are consistent with mild iodine deficiency for each of the groups of pregnant women. The evidence for mild iodine deficiency in these groups of pregnant women is consistent with recent Australian studies in pregnant and non-pregnant individuals. The association of ethnicity with iodine status is most likely due to differences in dietary behaviours. Understanding the factors that influence iodine nutrition in a multiethnic population will be important for identifying the most useful approaches to improving iodine status, evaluating different strategies and the development of appropriate monitoring programs. Action to improve iodine status in the Australian population should include consideration of ethnic differences in diet.