The main outcome of the study looked like this:
The observed effect is similar to the study I mentioned above, although in this case it just took more than 5 cups of coffee to cause an increase in the risk of death.
One interesting thing about this study was that the authors also looked into whether the pattern was true when including or excluding people who smoke.
That approach is very relevant because there is often a connection between smoking and coffee drinking.
However, the authors found that the overall results of the study were the same regardless of what group they considered. This indicates that the change in risk of death was not connected to whether or not people smoke.