# Folic Acid Advisories - A Public Health Challenge? - Discussion

Daniel Herrera, Fabrice Etilé

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Daniel Herrera, Fabrice Etilé. Folic Acid Advisories - A Public Health Challenge? - Discussion. European Workshop of Health Economics and Econometrics, Sep 2015, Paris, France. 15 p. hal-01602176

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# Folic acid advisories, a public health challenge?

Daniel Herrera-Araujo
(Toulouse School of Economics/INRA)

Discussion by Fabrice Etilé
(Paris School of Economics/INRA)
# Folic acid advisories, a public health challenge?

Daniel Herrera-Araujo
(Paris School of
Economics/Hospinnomics)

Discussion by Fabrice Etilé
(Paris School of Economics/INRA)
Research question & context

* Evaluation of an information campaign aiming at increasing folic acid intake in pregnant women, in order to lower the risk of Neural Tube Defects in newborns.

- NTDs: about 1/1000 births.

- Lifetime cost to society: about 600,000 US$ in 2002 (CDC, Yi et al., EurJPed, 2011); 242,948 Eur in 2005 (Netherlands, Jentink et al.,
# The 2005 campaign

## N'attendez pas d'être enceinte

## pour préparer au mieux votre grossesse

Il est important d'avoir des apports suffisants en **vitamine B9** au moment de la conception de votre bébé et en tout début de grossesse.

<figure><img src="image_2.png" /></figure>

### La vitamine B9 pourquoi ?

La vitamine B9, appelée aussi « acide folique » ou « folates » joue un rôle essentiel dans le développement du fœutus. Elle permet de réduire de manière significative les risques d'un retard de croissance ou de certaines malformations chez le bébé à naître.

<figure><img src="image_3.png" /></figure>

<figure><img src="image_4.png" /></figure>

### L'alimentation au quotidien

#### Fruits et légumes

<figure><img src="image_5.png" /></figure>

Cruis, crûs, frais, surgelés et en conserve. Les légumes verts (haricots verts, courgettes, petits pois, brocolis, épinards, mâche, avocat, cresson, etc.) et les fruits rouges (fraises, framboises, cerises) sont les plus riches en folates.

<figure><img src="image_6.png" /></figure>

<figure><img src="image_7.png" /></figure>

#### Lait et produits laitiers

<figure><img src="image_8.png" /></figure>

Le lait, les yaourts, le fromage peuvent s'inviter à table à chaque repas. Certains sont particulièrement riches en folates, comme les fromages à croûte blanche (camembert, brie) et ceux à pâte persillée (le bleu mais aussi le fromage blanc). Attention, la consommation de produits au lait cru est déconseillée aux femmes enceintes.

<figure><img src="image_9.png" /></figure>

Les repères de consommation, élaborés par le Programme national nutrition santé (PNNS) pour aider chacun à favoriser sa santé, permettent aussi de faire le plein de vitamine B9 ou folates !

<figure><img src="image_10.png" /></figure>

#### Pain, céréales, pommes de terre et légumes secs

<figure><img src="image_11.png" /></figure>

Le pain, le riz, les pâtes (surtout complets), les lentilles, les pois chiches, les pommes de terre, le maïs, contiennent des quantités intéressantes de folates.

<figure><img src="image_12.png" /></figure>

<figure><img src="image_13.png" /></figure>

#### Viande, poissons, œufs

<figure><img src="image_14.png" /></figure>

<figure><img src="image_15.png" /></figure>

Il est conseillé de les mettre au menu, en alternance, une ou deux fois par jour, en plus petit volume que leur accompagnement (légumes et/ou féculents).

Les œufs sont particulièrement intéressants sur le plan de la vitamine B9.

#### Petits conseils

Pour préserver la teneur en folates des légumes frais :

* conservez-les au réfrigérateur et consommez-les rapidement après l'achat ;

* évitez de les rincer trop longtemps ;

* privilégiez les cuissons à la vapeur ou à l'étouffée dans un peu d'eau bouillante.

<figure><img src="image_16.png" /></figure>

à volonté

#### Boissons : de l'eau

L'eau est la seule boisson indispensable.

<figure><img src="image_17.png" /></figure>

#### Matières grasses ajoutées, produits sucrés et sel

à limiter

Préférer le sel iodé.

<figure><img src="image_18.png" /></figure>

## pour préparer au mieux votre grossesse

### La vitamine B9 comment ?

Les experts recommandent un supplément de vitamine B9 sous forme de comprimés, prescrit par votre médecin, à prendre dès votre projet de grossesse et à poursuivre durant les trois premiers mois de votre grossesse. Parlez-en au professionnel de santé qui vous suit.

<figure><img src="image_19.png" /></figure>

Ce supplément complète la vitamine B9 apportée par l'alimentation. Pour une alimentation riche en folates, suivez au quotidien les repères de consommation donnés dans ce dépliant.

### Pas d'automédication

<figure><img src="image_20.png" /></figure>

N'achetez pas de compléments alimentaires sans en parler à votre médecin. En plus des folates, ils peuvent contenir d'autres vitamines ou oligoéléments dont la consommation en quantité élevée est contre-indiquée.

<figure><img src="image_21.png" /></figure>

<figure><img src="image_22.png" /></figure>

<figure><img src="image_23.png" /></figure>
Research question & context

- What has been the impact of this campaign on folic acid intakes?

- Debate on the cost-effectiveness of such policy as compared to food fortification actions:

• Obeid et al. (2015, Brth Defects Research), “Between years 2000 through 2010, a total of 7478 pregnancies with spina bifida and anencephaly out of approximately nine million births were caused by failure of European governements to introduce folic acid fortification on a population level”.

• Folic acid fortification would be cost saving if enrichment costs less than 20,000 Euro/QALY.

• But possible side effects at high doses: no systematic policy of flour fortification in France; some products are enriched in folic acid by manufacturers (e.g. breakfast cereals).

- Methodological challenge of evaluating a public health
Method

- Main challenge: the “control group”

- Most often no control group for the evaluation of information campaigns: before-after comparison and identification of a discontinuity in levels or trends, holding everything else constant => <u>credibility</u>?

- Here, only women who are going to have a baby are supposed to “take” the treatment: the other women form a “natural” control group...

• except that some of them may also “take” the recommendation: always-takers in the control group.

• (Fuzzy) DiD design in a reduced form approach + structural estimates.
Application

• Data & outcomes:

- Home scan data Kantar WorldPanel 2003-2008:

• nationally representative sample of households followed over four years on average.

• Very exhaustive information on purchases for food-at-home

• Only households with women meal planners are kept.

• Conversion in terms of nutrient intakes, using conversion matrices (CIQUAL) and an aggregation of products into 352 categories

- Outcomes of interest:

• Reduced-form approach: Quarter aggregation => average daily folic acid availability in a quarter by unit of ???? ("USDA adult equivalence scale" => adjustment for calorie needs?).

• Structural approach: demand-system estimate (food in nine categories) to identify a parameter of preference for folic acid.
# Results (1)

* Reduced-form approach:

- Treatment group Ti,t=1: if newborn at t or t+1.

- zi,t: folic acid intakes$Z_{i,t} = \alpha T_{i,t} + \delta_t + \lambda(T_{i,t} \times 1_{\{t>2004\}}) + \text{controls}$

* Positive & significant impact of the campaign for women without a college degree and/or having their first child.

- need to control for treatment*college, policy*college etc.. In Table 5 for investigating treatment heterogeneity?
# Discussion (1)

* Validity of the common trend assumption?

- DID Placebo analysis with policy in 2004 => not significant;

- Use of quaterly data for households who had a child: no impact on folic acid availability around the date of conception before 2005...

- *Is the common trend assumption valid for all types of households?* well-educated ones, those that already had a baby etc...

* (*SUTVA?* No interactions between the control and treatment groups? And between the treated (e.g. informal discussions between pregnant women)? Robustness check?)
# Discussion (2)

## Fuzzy DiD design:

<table><thead><tr><th></th><th>Treat =0</th><th>Treat =1</th></tr></thead><tbody><tr><td>Uninformed(D=0)</td><td></td><td></td></tr><tr><td>Being informed (D=1)</td><td></td><td>ATT of interest</td></tr></tbody></table>

- Not all targeted people actually get informed (D=1)

- $D \neq \text{Treat} * \text{Time}$

* De Chaisemartin and D'Hautfeuilles (2014)

## The estimated DID is a lower bound of the ATT of interest iff:

- The ATT does not vary with actual treatment or assignment (homogeneity?).

- Before the policy (Time=0), the proportion of “always-takers” (Informed: D=1) is lower in the control group (Treat=0) than in the treatment group.
# Discussion (3)

* Matching DiD?

- Table 1 suggests that there are important differences between treatment and control, and between treatment before and treatment after (e.g. College): Heckman, Ichimura and Todd (1997).

* Other controls: seasonal effects (births do not occur randomly in the year).

* No impact on well-educated because they already had well-balanced diets: implication in terms of equity/inequality?
# Results (2)

* Structural approach:

- A utility function that includes nutrient intakes

$$ 
\begin{align*}
u_i(x_i, y_i) &= \prod_{j=1}^{J+1} \left( \prod_{k=1}^{K^j} f_i(y_{ijk}) \right)^{\alpha_{ij}} \prod_{c=1}^{C} z_{ic}^{\beta_{ic}} \exp(\nu_i x_i) \\
z_{ic} &= \sum_{j=1}^{J+1} \sum_{k=1}^{K^j} a_{cj} y_{ijk} \\
f_i(y_{ijk}) &= \lambda_{ijk}^{\theta_{ij}},
\end{align*}
$$

$\omega_{ijt} = \sum_{c=2}^{C} \beta_{ic} s_{ijct} + \delta_{ij} + \xi_{jrt} + \epsilon_{ijt}.$

<figure><img src="image_24.png" /></figure>

- No prices?

- Identification of a change in preferences (DiD for $\beta$) by using exogenous shocks on $s_{ijct}$

* Interpretation of the +0.2 in terms of WTP for risk reduction (VSL: 17 ME)
Discussion (3)

• Validity of the identification strategy... or the threat of
"Industrial Disorganization"

- Not me: Angrist & Pischke (JEconPers, 2010).

- Strong parametric assumptions on consumer preferences

- IV for instrumenting sijct?

• Identify a group of households with the same purchase behaviour for food group j: those visiting mostly the same retailer the same day as household i for their purchases on j.

• For each j, compute the average nutrient content in c of all of the products that have been purchased at least once by a household in the reference group.

• Then compute the average “reference” share of j for its contribution to intakes of nutrient c

• Strong instrument but is the exclusion restriction valid?
# Discussion (4)

* Validity of the identification strategy...

- IVs:

* Standard problem of social interactions, with unobserved similarities between the household and households in its reference group.

* Source of exogenous variation? Day-to-day variations in the reference group & the choice set produced by inter-area variations in Sunday opening rules: you should state it more clearly and provide more evidence on it (large F-value...).

* No control for day fixed-effects?

- One way of convincing the reader: compare the predictions of your structural and reduced-form approaches for consumption.