Today's Pediatric Growth Charts

Factual Questions
21

I’m sorry, I thought I was clear. ??

You say you want to know what’s “normal”. But normal has two meanings, esp. in medicine:

  1. What’s healthy and good. Example: not having caries

  2. What most of the population currently does /has. Example: 90% of the population has caries.

So if the CDC is sending out current charts of what kids weigh today, these are normal type 2. BMI charts or related charts would be normal type 1. The value of normal type 1 is clear. What is the value of telling parents about normal type 2?

Again, I understand the need to measure and report height and weight for data. And changes in the personal growth chart of John Smith are important. Comparing John Smiths weight to normal type 1 is useful.
How is comparing John Smiths weight to type 2 normal in any way useful? A child that’s in the 10% percentile today might be in the 30% percentile in the 1980s, before the rise of obesity. That doesn’t change anything about the type 1 normal, the measure of healthiness on an “absolute” scale, or John Smiths personal scale.

22

Just because I don’t understand doesn’t mean you are not being clear.

The charts we have are what you call type 1, charts based on previous population norms, and for that reason. There is data collected that correlate your percentile grouping on those charts, and more tellingly, your change of position in those groupings, with various risks and outcomes. But some us quickly realize that something is wrong when we are told that pediatric obesity is defined as the top 5%ile and then in the next sentence told that 15% of kids today are obese. What? This is Lake Woebegone? Are they all above average too? If I am educating my patients (and their parents) about what their BMI means and showing them the percentile curves, then I need to tell them what those terms actually mean in this context.