Correlation, cause, longevity and reading books...

"This finding suggests that reading books provide a survival advantage due to the immersive nature that helps maintain cognitive status. "
20% actually?

 Bavishi, A., Slade, M.D., Levy, B.R., A chapter a day – Association of book reading with longevity, Social Science & Medicine (2016), doi: 10.1016/j.socscimed.2016.07.014.