Improvement in iodine status of pregnant Australian women 3 years after introduction of a mandatory iodine fortification programme

Introduction: In order to address population-level mild iodine deficiency in Australia, a mandatory iodine fortification programme of salt used in bread was introduced in late 2009. Methods: A before-after study was conducted to assess changes in median urinary iodine concentration (MUIC) measurements, according to supplement use, in convenience samples of pregnant women attending a public antenatal clinic in a regional area of New South Wales, Australia in 2008 (n=139), 2011 (n=147) and 2012 (n=114). Knowledge and practices related to iodine nutrition were investigated in 2012, using self-administered questionnaires. Results: The mild iodine deficiency confirmed pre-fortification (MUIC(IQR)=87.5 (62-123.5; n=110)) has steadily improved to 145.5 µg/L (91-252) in 2011 (n=106) and 166 (97-237) in 2012 (n=95) (sufficiency ≥150 µg/L). However, only women taking supplements containing iodine had MUIC indicative of sufficiency in both years surveyed post fortification (2011: 178 µg/L vs. 109 µg/L, P<0.001; 2012: 202 µg/L vs. 124 µg/L, P<0.05). Despite bread being the vehicle for iodine fortification, dairy foods remained major contributors to total iodine intake (58%). Overall knowledge regarding health implications of iodine deficiency was poor. Conclusions: Iodine status of women has improved since the introduction of mandatory iodine fortification; however supplementation is indicated during pregnancy.