Nope, not health care.

Mark Thoma writes

The vast majority of observers agree that we will need to address the debt problem, which is mostly a health care cost problem, at some point.

Mostly a health care problem??? Here. Here's a graph of debt:

How does health care cause this?

It's three colors because there are three sources for the debt numbers. It doesn't matter. Answer the question: How does "health care" make debt do this?

It doesn't.