Prevalence of Folate Deficiency in Korean Women of Reproductive Age Using a Serum Folate Assay Traceable to the WHO International Standard

Background: We aimed to investigate serum folate level in Korean women of reproductive age and to evaluate the prevalence of folate deficiency by age using different cutoffs. Methods: We retrospectively reviewed data obtained with a serum folate assay traceable to World Health Organization international standard reference material 03/178. Results: Between September 2017 and June 2019, data from a total of 8,380 Korean women aged 15 -49 years were obtained. Mean (standard deviation) serum folate concentration for all women was 9.1 (6.7) ng/mL. Prevalence of folate deficiency using the cutoff of < 3 ng/mL was 6.2% and that for < 4 ng/mL was 14.9%. The prevalence of folate deficiency was higher in women of younger age (15 to < 25 years, even > 30% using the cutoff of 4 ng/mL) compared to other age groups. Conclusions: This study suggests that women aged 15 to < 25 years are at high risk of folate deficiency.