What has been tested.
Where the gaps are.

Rows are pathway blocks: a risk factor first, then the interventions that act on it, so a column reads as a causal chain from population evidence to trials. Risk-factor rows count published association papers, and a risk factor with no paper in this release is left out; intervention rows count registered trials, darker for more, with the amber line showing how many link to a publication. A blank cell is a gap.