Many people want to write a history of their field, or lots of statistics about a disease in the Significance. These points are only helpful to the reviewer in the context of the work that you propose to do. So, as stand-alone facts they may be true, but how do they help convince the reviewer that your grant is meritorious? To write a compelling Significance statement, it has to be specific to your proposed work, and you need to be explicit about stating the significance of the research. It does not have to solve everything, but at least build a path towards some greater scientific or clinical vision and benefit to society.
Here is an explanation of how I write my significance section and check my own work and that of others.