Trends in prevalence of megaloblastic anemia in US adults: comparative analysis of pre- and post-folic acid fortification surveys

Abstract

Folic acid fortification had a significant impact on folate status in the US. It is not known whether folic acid fortification had any impact on the prevalence of megaloblastic anemia in US adults. Therefore, we investigated the impact of folic acid fortification on prevalence of megaloblastic anemia and mean corpuscular volume (MCV) in those with low RBC folate concentrations (<362.6 nmol/L) utilizing the data from the National Health and Nutrition Examination Surveys, 1988- 1994, 1999–2000, and 2001–2002. Across the three surveys, prevalence of anemia was higher in older persons compared to younger persons, in non-Hispanic black men compared to non-Hispanic white men, and in those who consumed vitamin/mineral supplements than those who did not consume vitamin/mineral supplements. Overall, prevalences of megaloblastic anemia (MCV >98 pmol/L) for men were 3.4%, 3.3%, and 3.5% in 1988–1994, 1999–2000, and 2001–2002, respectively and for women were 2.9%, 4.0% and 3.9% in 1988–1994, 1999–2000, and 2001– 2002, respectively. MCV values for men in 1988–1994, 1999–2000, and 2001–2002 were 90.2 pmol/L, 90.7 pmol/L, and 90.3 pmol/L, respectively and for women in 1988–1994, 1999–2000, and 2001–2002 were 90.1 pmol/L, 90.3 pmol/L, and 89.8 pmol/L, respectively. These prevalences of anemia and MCV were not significantly different between pre- and post-folic acid fortification surveys. Similar trends were observed in various age, race-ethnicity, poverty income ratio groups. This suggests that folic acid fortification had no impact on prevalence of megaloblastic anemia in the US.