Folic Acid-Fortified Iodized Salt and Serum Folate Levels in Reproductive-Aged Women of Rural India: A Nonrandomized Controlled Trial

Abstract

Importance: India has a disproportionately high prevalence of neural tube defects, including spina bifida and anencephaly (SBA), causing a high number of stillbirths, elective pregnancy terminations, and child mortality; India contributes a large proportion of the global burden of SBA. Thirty years after folic acid was shown to be effective in reducing SBA prevalence, only about one-quarter of such births are prevented globally through cereal grain fortification. Objective: To determine the association of folic acid-fortified iodized salt with serum folate concentrations among nonpregnant and nonlactating women of reproductive age. Design, Setting, and Participants: This nonrandomized controlled trial using a preintervention and postintervention design was conducted in 4 rural villages in Southern India from July 1 to November 30, 2022. All households in the villages agreed to participate in the study. Preintervention and postintervention serum folate levels were analyzed among study participants at baseline and after 4 months, respectively. Intervention: Consumption of approximately 300 µg/d of folic acid using double fortified salt (folic acid plus iodine). Median serum folate concentrations were assessed at baseline and 4 months. Main Outcomes and Measures: Change in median serum folate levels between baseline and study end point as the primary outcome of the study. Results: A total of 83 nonpregnant nonlactating women aged 20 to 44 years (mean [SD] age, 30.9 [5.1] years) were eligible for the study and provided serum samples for analysis at baseline and the end point of the intervention. The median serum folate concentration increased from 14.6 (IQR, 11.2-20.6) nmol/L at baseline to 54.4 (IQR, 43.5-54.4) nmol/L at end of study, a 3.7-fold increase from baseline to study end point. Two-tailed Wilcoxon signed rank test showed the median difference in preintervention and postintervention serum folate concentrations to be highly significant (P