26% of why some children develop CD

[maayani]

Hello,

Heredity explains only up to 26% of why some children develop CD.
(Crohn disease)

Healthcare Professionals

I just want to make sure: to what refer here "26%"? 26% of Crohn cases?

Thanks in advance.

 

[Keith Bradford]

Strictly speaking, the word "why" acts as a kind of noun meaning "the reasons". I.e. there are perhaps 100 reasons why some children develop CD. Heredity explains only up to 26% of those reasons.

Now, whether that is exactly what the writer intended is not certain in my mind. He may have meant what you said; I would need to be a scientist to be sure.

 

[Myridon]

The sentence is poorly written. Perhaps it's 26% of the only reason. "The word "sentence" is 20% of the first sentence in this post (1 in 5 words = 20%)."
I hope they mean "Heredity only explains 26% of the cases of CD in children."

 

[entangledbank]

This seems to be the difficult subject of heritability. It's not 26% of cases (I think), but 26% of the contribution. If identical twins are studied, you can see how much variation (on average) relates to inheritance and how much to environmental or random factors.