Reply to “The Fallacy of Using Administrative Data in Assessing the Effectiveness of Food Fortification. Comment on: Folic Acid Fortification and Neural Tube Defect Risk: Analysis of the Food Fortification Initiative Dataset. Nutrients 2020, 12, 247”
1. Introduction
2. Ecological & Exception Fallacies
3. Confounding Issues Associated with the Study
4. Literature
5. Response to Major Limitations Cited by Kancherla et al.
- (1)
- “The modeled prevalence estimates for neural tube defects used in their analysis have inherent biases and limitations, and they underestimate the true prevalence of NTDs for many developing countries that lack birth defect surveillance. They are mainly intended to provide policy makers with a crude burden of NTDs and not for scientific hypothesis-oriented research”. We utilized NTD prevalence estimates reported by the FFI, who cite Blencowe et al. [11] for the majority of their estimates. In Figure 1, we obtain similar results using NTD prevalence estimates from Kancherla et al. [5]. These are the only publicly available estimates for many countries and are the data used to promote the national fortification of cereal grains;
- (2)
- “FFI’s individual country profiles that contain grain fortification-related information are intended for stakeholders in the flour and milling industry, and organizations and policy-makers invested in grain fortification. Their variable, “Folic acid fortification measured in ppm” is an incomplete measure of fortification reach and impact. The average fortification levels are meaningless without integrating data on the average grain availability for a country. A low fortification level in a country with high grain availability, would have a very different fortification impact compared to a low fortification level in a country with low grain availability”. On the surface, this argument is reasonable in that the average grain availability for a country will affect the impact of fortification. There will be countries with high grain availability and others with low grain availability. We agree that our variable of folic acid fortification measured in ppm does not take into account reach and impact. This was encompassed in our discussion of the confounding issues related to variations in consumption of folic acid, the accuracy of data reporting agencies, voluntary fortification with folic acid, periconception folic acid supplementation, and variable implementation timing of mandatory folic acid programs. However, our analysis showed an equivalent average as well as a range of high and low values for NTD per 10,000 births with and without fortification. One would expect that if national fortification was working, then there should be at least a trend toward less NTD in the fortification cohort compared to no fortification. In addition, using fortification program coverage data generated by Kancherla et al. [5], a linear regression analysis indicated a very weak correlation between NTD prevalence and the level of folic acid consumed from fortification (Figure 1), which was similar to our reported result;
- (3)
- “Fortification coverage in a country was not considered available online …. Several countries have a mandatory fortification policy, but where fewer than 100% individuals consume fortified food”. Please see Figure 1 and the associated discussion. The consideration of fortification coverage at both 100% and 91% or greater, with coverage rates reported by Kancherla et al. [5], did not change the results. Even with mandatory fortification, it is highly unlikely that 100% of individuals consume fortified cereal grains. For example, individuals with Celiac disease do not consume wheat;
- (4)
- “Population reach of fortified foods, which indicates actual consumption of fortified foods, was not considered. Analyzing population averages fortification levels (ppm), without considering the reach and coverage of the fortified product, masks differences found between consumers and non-consumers”. We agree that population-level observational studies of food fortification mask differences between consumers and non-consumers. Optimal research would include a combination of population- and individual-level studies. Data is not available at the individual level and it is at the individual level that folic acid may interact with medications, genetic variations or other factors to help or harm health;
- (5)
- “Other reviews showing effectiveness of fortification on NTD prevention were not cited”. We address this criticism above in the Literature section;
- (6)
- “Several supporting factors including fortification type (voluntary vs. mandatory), country-specific policies on elective termination for NTD-affected pregnancies, stillbirth proportions among those with NTDs, fortification implementation and coverage were not considered”. We address the mandatory fortification and coverage criticisms in Figure 1. Regarding the abortion rates of NTD-affected pregnancies, of the top 10 countries with the highest number of abortions (Greenland, Russia, Hungary, Cuba, Nagarno-Karabakh, Czech Republic, Estonia, Martinique, Bulgaria, and China), NTD estimates per 10,000 births are available from the FFI for seven countries (Russia, seven; Hungary, 10; Cuba, eight; Czech Republic, 10; Estonia, nine; Bulgaria, 30; China, 19). In this group, Cuba is the only country with mandatory fortification of folic acid. The Kancherla et al. data report 13 cases of NTD per 10,000 live births in Cuba [5]. With this small dataset, NTD estimates range from 7–30, with an average of 14.17 per 10,000 births in countries that do not have mandatory fortification, but do have a high number of abortions, suggesting that the elective termination of NTD-affected pregnancies is likely not a confounding factor in the population analysis.
6. Conclusions
Author Contributions
Funding
Conflicts of Interest
References
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Westmark, C.J.; Murphy, M.E. Reply to “The Fallacy of Using Administrative Data in Assessing the Effectiveness of Food Fortification. Comment on: Folic Acid Fortification and Neural Tube Defect Risk: Analysis of the Food Fortification Initiative Dataset. Nutrients 2020, 12, 247”. Nutrients 2020, 12, 1335. https://doi.org/10.3390/nu12051335
Westmark CJ, Murphy ME. Reply to “The Fallacy of Using Administrative Data in Assessing the Effectiveness of Food Fortification. Comment on: Folic Acid Fortification and Neural Tube Defect Risk: Analysis of the Food Fortification Initiative Dataset. Nutrients 2020, 12, 247”. Nutrients. 2020; 12(5):1335. https://doi.org/10.3390/nu12051335
Chicago/Turabian StyleWestmark, Cara J., and Michaela E. Murphy. 2020. "Reply to “The Fallacy of Using Administrative Data in Assessing the Effectiveness of Food Fortification. Comment on: Folic Acid Fortification and Neural Tube Defect Risk: Analysis of the Food Fortification Initiative Dataset. Nutrients 2020, 12, 247”" Nutrients 12, no. 5: 1335. https://doi.org/10.3390/nu12051335
APA StyleWestmark, C. J., & Murphy, M. E. (2020). Reply to “The Fallacy of Using Administrative Data in Assessing the Effectiveness of Food Fortification. Comment on: Folic Acid Fortification and Neural Tube Defect Risk: Analysis of the Food Fortification Initiative Dataset. Nutrients 2020, 12, 247”. Nutrients, 12(5), 1335. https://doi.org/10.3390/nu12051335