Long-term weekly iron-folic acid and de-worming is associated with stabilised haemoglobin and increasing iron stores in non-pregnant women in Vietnam

Abstract

Background: The prevalence of anaemia and iron deficiency in women remains high worldwide. WHO recommends weekly iron-folic acid supplementation where anaemia rates in non-pregnant women of reproductive age are higher than 20%. In 2006, a demonstration project consisting of weekly iron-folic acid supplementation and regular de-worming was set up in two districts in a northern province in Vietnam where anaemia and hookworm rates were 38% and 76% respectively. In 2008 the project was expanded to all districts in the province, targeting some 250,000 women. The objectives of this study were to: 1) examine changes in haemoglobin, iron stores and soil transmitted helminth infection prevalence over three years and 2) assess women's access to and compliance with the intervention.

Methods and findings: The study was a semi-cross-sectional, semi-longitudinal panel design with a baseline survey, three impact surveys at three-, twelve- and thirty months after commencement of the intervention, and three compliance surveys after ten weeks, eighteen and thirty six months.

Results: After thirty months, mean haemoglobin stabilised at 130.3 g/L, an increase of 8.2 g/L from baseline, and mean serum ferritin rose from 23.9 µg/L to 52 µg/L. Hookworm prevalence fell from 76% to 22% over the same period. After thirty six months, 81% of the target population were receiving supplements and 87% were taking 75% or more of the supplements they received.

Conclusions: Weekly iron-folic acid supplementation and regular de-worming was effective in significantly and sustainably reducing the prevalence of anaemia and soil transmitted helminth infections and high compliance rates were maintained over three years.

Figure 1. Flow chart of implementation and evaluation of weekly iron-folic acid supplementation and regular de-worming intervention with number of samples analysed from each survey.

Figure 2. Flow chart of newly-enrolled and follow-up participants.

Figure 3. Estimated absolute changes in haemoglobin from baseline and the ratios of follow-up serum ferritin and soluble transferrin receptor relative to baseline; 95% confidence intervals are shown as vertical bars around each estimate and were computed using linear mixed models to take account of study design.

# This figure shows the results of the mixed-effects model and non-overlapping confidence intervals indicate statistical significance.

Figure 4. Estimated odds ratios for anaemia, iron deficiency and iron deficiency anaemia relative to baseline; 95% confidence intervals are shown as vertical bars around each odds ratio estimate, and were computed using logistic mixed models to take account of study design.

# This figure shows the results of the mixed-effects model and non-overlapping confidence intervals indicate statistical significance.

Figure 5. Estimated odds ratios for each species of soil transmitted helminth relative to baseline; 95% confidence intervals are shown using vertical bars and were computed using logistic mixed models to take account of study design.

# This figure shows the results of the mixed-effects model and non-overlapping confidence intervals indicate statistical significance.