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

•In 2009, Australia introduced mandatory iodine fortification of salt in bread.•Before–after surveys indicated improvements in iodine status in pregnant women.•Median urinary iodine concentrations improved, to sufficiency in 2011–12.•Only women who consumed iodine-containing supplements were iodine replete.•Strategies to improve supplement use in pregnant women in Australia are warranted.

IntroductionIn 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.MethodsA 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.ResultsThe 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.ConclusionsIodine status of women has improved since the introduction of mandatory iodine fortification; however supplementation is indicated during pregnancy.