Yeah, that seems curious. But nowadays, you can just ask. So I asked ChatGPT and it listed a wide variety of factors.

> Researchers generally group explanations into (1) cause-of-death differences, (2) exposure/behavior differences, (3) healthcare-use differences, and (4) biological differences.

https://chatgpt.com/share/697ec925-3ab0-8000-9a09-d47d2fb33d...