Now we're going to be talking about the major indicators and how they're collected in relationship to nutrition and growth. The idea is that measures of nutrition and nutritional impact and growth in children are all primarily based on two different areas. One is anthropometry. Basically you're trying to get information about growth in terms of how tall or length, weight, maybe birth weight, all these collecting middle arms circumference we'll talk about later, that ideas of really you're tracking growth as a indicator. Then the second is micronutrient status that talks about well dietary intake that are they actually getting all the things they need. This is in some ways more of a risk factor for sub-optimal growth or poor health outcomes. Finally, we'll talk a little bit how you combine these different measurements to come up with key indicators of nutritional impact. Let's look at growth as nutritional indicators or impact related to nutrition. The idea is that for children or adults, what you need is a measure of weight, a measure of length or height, and a measure of age. Then with that, we create some summary statistics. Now, all of these summary statistics you see below are based on z-scores. You're simply comparing the child's growth for age, whether it's weight for age, or length for age, or weight for length to other children or other that age cohort. The idea is that you're simply comparing how are they to the standards. Many people when they have babies they're told, "Your child is in the 95th percentile, it's the sixth percentile." The idea is you have a normal distribution and they're simply comparing your growth rates both in terms of height and weight for their age to other cohorts. Now, one of the things for me, I'm not a nutrition expert and we have a picture of there measuring a child. That's why we say, we'll link through HAZ. I always thought, well, the nice things about the nutrition indicators is that they're very exact. In fact, one of the real difficulties, especially with young children, is getting accurate measures of, weight is not so hard, but link through HAZ is very difficult. There's someone explained to me, she said, "You notice the woman there, there's one hand trying to hold the child down and spread them out to get an accurate measure of length. " But if done well, these can provide very reliable, robust measures of growth. The idea is that for your primary indicators that again, when you're comparing two standards, what happens WHO is compiled growth standards from multiple countries to say what happens. They've also recently in the last few years redone those where they're trying to select and make sure they're eliminating people in growth standards that have health issues. Therefore, what they find is across all countries, it really doesn't matter if you're in Nepal or Bangladesh, or in Uganda, or in the US, the actual growth curve is almost identical. There's no evidence of any difference once you've eliminated effects of malnutrition or infection. Now with growth, there's three clear indicators that people use as an impact measure. Stunting which is HAZ- for- age. It's where they are in the HAZ-for-age z-score. Children that are more than two standard deviations below the average in that distribution for HAZ-for- age are referred to as stunted. Wasting is defined as weight for Linksys score. Again, using minus two is the cut-off, that children that are minus 2 or below are referred to as wasting. An underweight is weight for age. Again, this indicator underweight is less frequently used because it doesn't combine weight with length. The key is for stunting is a primary measure of longer-term undernutrition and takes longer to respond to intervention. The idea is that stunting reflects a long period of malnutrition. That also you'll find is very hard to undo after the first two years of life. Wasting, on the other hand, reflect short-term malnutrition and can change relatively quickly. Again, you think about for someone their weight can drop fairly quickly if they have insufficient food to eat for three or four month period, but then it can be brought back up, weight can be brought back up by simply providing more foods. Both of these are highly important risk factors for other causes of mortality, especially infectious diseases. Now for mothers, they're slightly different and also for kids, it's becoming more important. The idea of overweight is a long-term health problem. Overweight women are more likely to have poor birth outcomes. They're also apt to more susceptible getting diabetes, also obese. That's usually defined for older women by body mass index. If you have a body mass index of 25 or more, that you're defined as overweight and that's a risk factor. Obesity can also be used with a BMI of 30 or more for adults, but also obesity is more and more being a focus of young children that with malnutrition or early feeding habits can lead to obesity and they're usually what they're using is again like the flip side of wasting their weight for link z. If you're above the higher categories, above plus two, sometimes that's defined as obesity in children. Though generally it's not a major focus in most low-income country programs. WHO growth standards, what they've done is, they've provided these gross standards again, compiling data from all countries, the inner growth. It was originally done for all information. There was the INTERGROWTH standards were developed in about 2012 or '14, where again, they only selected people to include that had no malnutrition problems or general health problems. They tried to control for that and suggest here's what the growth pattern should look like without any health issues or malnutrition issues. Again, finding that there aren't differences between countries and we have a much more robust standard of what growth should look like for the first five years of life. Just to give you quickly reviewing what I said before. If you look at our major indicators, the idea is that again, according to z-scores that the people, when you're looking at weight for age, it's underweight or severely underweight. Then you have length for height, is again, if you're minus 2 is stunted, minus 3 is severely stunted and then wasting again is weight for length, wasted moderate or acute wasting, and then severe acute malnutrition. The idea is that normally when this happens, when you'll see later when we collect data, all your children are thrown into these categories, not based on the distribution within their population, but within the global distribution of what we expect for children. Another way of measuring wasting again is MUAC, mid-upper arm circumference, always love that MUAC, as an alternative to actually weighing the child and laying them down and getting length. This is primarily used in emergency situations because it's very easy to do. You see on the right, they simply can measure the circumference of the child. It's a very good indicator, is good as we get from the normal anthropometry and is much easier to do. It's a good prediction of mortality. It's a very good proxy for what we've defined as wasting before and you don't really have to do age adjustments. It's something that is primarily used in emergency situations where they don't have time to do the full weight and length measurement. As I said earlier, getting length of young children is much more difficult and error-prone exercise. MUAC is very good at that, doesn't give you any information obviously about stunting because there's no length or height variable, but it's something that's being used more and more. Now, you see here on the right, we've just added now to our earlier table the mid-upper arm circumference into the same thing of what would classify as moderate acute malnutrition and severe acute malnutrition. The idea is, the other things we've got these ratios thing here, again with standards of what the size should be. The next thing you have to think about when you're looking at impact related to nutrition is how actually nutrition works. As we said earlier, the idea of stunting reflects long-term changes or long-term malnutrition where wasting is more temporal. It can be short-term. In fact, if you look at wasting, often what happens is if you go out and run a survey that is prior to harvest time or in the poor part of the year that you'll find more wasted children, then a month or two after harvest, you would get a completely different score on wasting or percent of the children who are wasted simply because they have more food availability. Wasting is very up and down and so you still have to concern yourself with timing that if you're looking over multiple time periods in an evaluation and you want to look the measure of the change in wasting, you've got to ensure that you're measuring in the same time period of the year and you've got concerns about conceptual factors like rain or market disruptions in agriculture that could have a big effect on wasting. Stunting is a little different. Stunting is a long-term effect and therefore interventions are going to take longer to actually change and as you can see here in this graph the bottom line, that basically what happens with stunting is most of the stunting occurs in the first two years of life. Then after that two-year period, basically you don't catch up. In fact, it's the holy grail for people doing research in this area is trying to show if we intervene after age 2 can we actually shift those stunted children into non-stunting status. In fact, so far there has been no evidence that that can occur. The real tricky part with wasting is very quick to change but you have to worry about conceptual factors. Stunting is very difficult to change even in the first two years of life but certainly after that you're not going to find a change in wasting. It also means that probably what you're going to have to look at as an indicator for stunting is only stunting rates in the first two years of life not in all children under five simply because you're not going to have effect at those older ages unless you've intervened in the first two years of life. Additional indicators of nutritional impact. One of the things that people use a lot for mothers is anemia. Anemia is strongly related to poor birth outcomes, especially preterm birth. They normally define anemia differently for pregnant women and just women of reproductive age, your anemia levels characterization is lower in terms of the amount of iron content. It's also not simply nutrition-related. Lots of anemia is not related to iron deficiency, our standard thing but also related to other diseases and infections such as malaria. Birth weight is another critical output for children that people often use. Earlier we had talked about with stillbirths, this idea of gestational age, the ideal outcome would not be birth weight but would be birth weight or in-gestational age, so you could talk about pre-maturity. Is the child premature or is the child small for gestational age due to intrauterine growth retardation? But to do that you would have to have some measure of gestational age. Primarily what has been done is they've used birth weight, that it is not only related to the probability of death of a young child especially during the neonatal period but it also is predictive of sub-optimal growth after birth. Stunting, the probability of being stunted is strongly related to low birth-weight. To go a little more in depth in terms of anemia as a nutritional outcome for mothers, you're going to see here in the graph on the right many factors influence anemia and so it's a very difficult indicator to use for evaluation of program because often programs do one or two things; they might provide iron but in fact, that's not the only source of anemia. That for most countries in Sub-Saharan Africa, only about 40-45 percent of anemia is iron deficiency anemia. Instead, other things like malaria drive it. It is a common indicator that people use the percent of women, the 15-49 with anemia, they often do it by levels of severity, but it's very difficult not to measure, if you're willing to draw blood you can measure it, but attribution of the change in anemia to your program, so you're going to have to have a very complex model change, complex on the right and track all of those different things that are related to anemia if you're going to use anemia as an impact measure of your program. Now what we're going to do is having laid out what the different indicators are related to nutrition and growth, we're going to talk about methods and sources of information on this that can be used in evaluations.
