Malaysia's puzzling case with anaemia among children
Since 2001, Malaysia suffered the worst setback in anaemia levels among children worldwide. Most countries improved.
You have anaemia when your blood cannot transport oxygen fast enough to your body parts.
Specifically, oxygen is carried by proteins called hemoglobin in our red blood cells. Hemoglobins catch oxygen with iron-fused stickers called heme. If your hemoglobin levels are too low, you are diagnosed with anaemia.
I have been looking at iron-deficiency and anaemia for one of my food classes at Harvard.
Reporting
One of the first things I did was to look up trends of anaemia levels. (Ode to data digging habits.) Logically, the first place to dig is the World Health Organisation datasets.
I narrowed my initial efforts to children age 6 months to 59 months (i.e., younger than 5 years), and the period from 2001-2019 (20 years). I downloaded the data, discarded parameters I did not need, and focused on 1) overall trends in anaemia levels, 2) Malaysia's record, 3) patterns between countries that reduced anaemia or not.
Results
- WHO's dataset contains records for 192 countries/territories.
- Good news! Anaemia levels have declined in 73% of the countries since 2001 (140 out of 192 countries). In these countries, a small proportion of young children had anaemia in 2019 than in 2001.
- Bad news! Anaemia levels increased in 27% of the countries since 2001 (52 out of 190 countries). In these countries, a bigger proportion of young children had anaemia in 2019 than in 2001.
- Strange news! Most of the countries with increased anaemia levels are developed countries (e.g., Australia, many European countries, Canada, Japan, South Korea, Singapore).
- Most surprising news! Malaysia had the highest gain in anaemia level worldwide with 4.8 percentage point. Malaysia was an outlier among the gainers – 2nd place France only had 4 percentage point gain, and Malaysia was the only developing economy among the worst 5 performers.
Top 5 Biggest Decline in Anaemia Levels Among Young Children
(The higher up in the table the better)
| Country | 2001(%) | 2019(%) | Change |
|---|---|---|---|
| Uzbekistan | 47.6 | 21.9 | -25.7 |
| Guatemala | 32.8 | 9.8 | -23 |
| Gambia | 75 | 2.3 | -22.7 |
| Bhutan | 66.5 | 44.7 | -21.8 |
| Rwanda | 59.1 | 37.9 | -21.2 |
Top 5 Biggest Increase in Anaemia Levels Among Young Children
(The higher up in the table the worse)
| Country | 2001(%) | 2019(%) | Change |
|---|---|---|---|
| Malaysia | 19.8 | 24.6 | 4.8 |
| France | 10.7 | 14.7 | 4 |
| Belgium | 13.6 | 17.4 | 3.8 |
| Netherlands | 11.9 | 15.5 | 3.6 |
| Germany | 11.6 | 15.1 | 3.5 |
Source: World Health Organisation
Questions
I have many. I posted the map above on my social media (including LinkedIn), and nobody seems to have a clue on Malaysia's anaemia trends. I also haven't found studies that pointed this out, much less explain it.
But I suspect that whatever reasons drove the increases in anaemia among young children, they might be different between Malaysia and the developing nations.
Also, the cut-off thresholds in hemoglobin levels used to diagnose anaemia (recommended by WHO and practiced worldwide) have been debated. It's basically a statistical estimation. Scientists sampled groups of people who appeared healthy, measured their hemoglobin levels, plot the spread on a graph, and take the lowest 5% percentile as a cut-off point for anaemia.
In other words, if your hemoglobin level is lower than that seen in the lowest 5% of healthy individuals, then you have anaemia. The 5% threshold is arbitary – why not 2%? Why not 10%? Also, which healthy individuals? The WHO thresholds were built on samples of mainly Caucasians in Europe and North America. WHO acknowledges the shortfall of limited sampling.
Yaw Addo et al. (2021) compared the WHO thresholds for anaemia diagnosis against two other datasets (BRINDA and VMIS) which were more global and diverse. They used the same 5% percentile method. They found that the more diverse datasets produced lower cut-off points than the WHO's. The results suggest that WHO's thresholds have led us to diagnose more people as anaemic than not.
Nevertheless, the debate doesn't seem to explain Malaysia's apparent outlier status among the countries that suffered a fallback in anaemia management.