Folate awareness and the prevalence of neural tube defects in South Australia, 1966-2007.

OBJECTIVES: To ascertain changes in: women's knowledge of the role of folic acid in the prevention of neural tube defects (NTDs); intake of folic acid among pregnant women; and prevalence of NTDs in South Australia.

DESIGN, SETTING AND PARTICIPANTS: Computer-assisted telephone interviews of South Australian households from 1994 to 2007 over a period encompassing a statewide folate promotion campaign (1994-1995), continuing folate promotion, as well as the introduction of voluntary folate fortification of foods (1996); ascertainment of the total prevalence of NTDs from births and terminations of pregnancy from 1966 to 2007.

MAIN OUTCOME MEASURES: Changes in women's knowledge of the role of folic acid in the prevention of NTDs; changes in the prevalence of NTDs.

RESULTS: From 1994 to 2006 and 2007, knowledge about the role of folic acid increased from 25% to 77% (P < 0.001) and knowledge that folic acid needs to be taken in the periconceptional period increased from 12% to 39% (P < 0.001). The proportion of pregnant women who increased their periconceptional intake of folate rose from 61% in 1998 to 81% in 2006 and 2007 (P < 0.001), with significant increases in the consumption of fortified cereals (from 15% to 29%) and folic acid tablets (from 37% to 64%). The total prevalence of NTDs fell from 2.06 per 1000 births in 1986-1990 to 1.23 per 1000 births in 2002-2007 (relative risk, 0.60; 95% CI, 0.48-0.74; P < 0.001).

CONCLUSIONS: Folate promotion and voluntary fortification of certain foods with folic acid were associated with increased awareness of the role of periconceptional folic acid, increased folate consumption and a reduction in the prevalence of NTDs in South Australia by 40% (95% CI, 26%-52%).