The second study has a classic ‘adjusting for observed confounders’ methodology which comes with classic limitations such as that you don’t observe all confounders. For example, they control for alcohol, drug abuse, but not smoking (!)
The first study also acknowledges possible confounding but I haven’t checked it in detail.
The second study has a classic ‘adjusting for observed confounders’ methodology which comes with classic limitations such as that you don’t observe all confounders. For example, they control for alcohol, drug abuse, but not smoking (!)
The first study also acknowledges possible confounding but I haven’t checked it in detail.