Low proportions of folic acid deficiency after introduction of mandatory folic acid fortification in remote areas of northern Queensland, Australia: a secondary health data analysis.

Background

Australia implemented mandatory folic acid fortification of bread-making flour in 2009.

Objective

To assess the impact of folic acid fortification in remote vs. regional urban areas and Indigenous vs. non-Indigenous populations in northern Queensland.

Methods

Routinely collected data on folic acid measurements in remote areas and two regional urban centres in northern Queensland between 2004 and 2015 were analysed (n = 13,929) dichotomously (folic deficient vs. non-deficient).

Results

Overall prevalence of folic acid deficiency was 3.2% (235/7282) in urban centres compared with 7.2% (480/6647) in remote areas (p < 0.001), and 9.3% (393/4240) in the Indigenous population compared with 3.2% (273/8451) in the non-Indigenous population (p < 0.001). Prevalence of folic acid deficiency dropped from 12.2% (n = 481) in 2004-2008 to 1.5% (n = 126) in 2010-2015 (p < 0.001). This translates into a relative risk reduction (RRR) of 88%. RRR was 79% (7.2% vs. 1.5%) in urban centres, 91% (17.3% vs. 1.5%) in remote areas, 92% (20.5% vs. 1.6%) in the Indigenous population and 80% (7.4% vs. 1.5%) in the non-Indigenous population (p < 0.001 for all).

Conclusions

Substantial declines of folic acid deficiency to low and comparable proportions in former high-risk populations indicate that mandatory folic acid fortification of flour has had a population-wide benefit in northern Queensland.