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# Chronic malnutrition rate interpretation

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### Mark Myatt

Consultant Epidemiologist

Frequent user

20 May 2010, 13:33

I don't know about the "latest" in interpreting chronic malnutrition "rates". I am also not sure about assessing "food security" using a combined indicator since the term "food security" tends to have quite a broad definition. Having said that ... I think you might be looking for something like the "composite index of anthropometric failure" (CIAF) which uses W/H, H/A, and W/A to create a composite indicator. The index is quite simple to calculate: (1) Do your survey (SMART, 30-by-30, &c.). (2) Calculate and add W/H, H/A, and W/A indices (z-scores) (3) Apply the usual case-definitions for each indicator (i.e. WHZ < -2, HAZ < -2, WAZ < -2) so you have three YES/NO variable indicating wasting, stunting, and underweight for each child. (4) Apply grouping case-definitions: (A) wasting = NO, stunting = NO, underweight = NO (B) wasting = YES, stunting = NO, underweight = NO (C) wasting = YES, stunting = NO, underweight = YES (D) wasting = YES, stunting = YES, underweight = YES (E) wasting = NO, stunting = YES underweight = YES (F) wasting = NO, stunting = YES, underweight = NO (Y) wasting = NO, stunting = NO, underweight = YES (5) Count the number in each group. (6) Calculate the CIAF as [(B + C + D + E + F + Y) / N] * 100 where "N" is the total number of children (i.e. A + B + C + D + E + F + Y). This simplifies to [(N - A) / N] * 100. See http://tinyurl.com/2unqmq7 for a fuller discussion of the CIAF. I think that the CIAF is an interesting attempt at a composite index. The use of W/H instead of MUAC is problematic as W/H is biased by body-shape. You could replace W/H with MUAC. This would make a better indicator. Also you'll need to be careful about what you do with oedema as this will upwardly bias both W/H and W/A. You could include oedema in your case-definition of wasting but (C), (D), (E), and (Y) will be biased downward. This might be a problem in setting where oedema is common (e.g. Malawi, DRC, &c.). You also have to be aware that the H/A and W/A indices can be very prone to error when age data is not accurate. The key reference is "Svedberg P (2000), Poverty and Undernutrition: Theory, Measurement, and Policy. Oxford: OUP" which you can read online at: http://tinyurl.com/38xywn5 More on the CIAF (i.e. examples of its use and some test cases) can be found at: http://tinyurl.com/3252s6q http://tinyurl.com/36uu57n http://tinyurl.com/3yjdfc9 http://tinyurl.com/3xx7vfg http://tinyurl.com/3x478e4 http://tinyurl.com/366ndd8 I hope this helps.

### Chris Hillbruner

DCOP - FEWS NET

Normal user

8 Oct 2015, 15:27

This is another interesting example of using CIAF, in this this case to explore the relationship between mortality risk and the presence of multiple anthropometric deficits.

http://ajcn.nutrition.org/content/97/4/896.full

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