Lol. Is 'Correlation is not casuation' how you try to discount studies you don't understand? You can't even spell 'causation' lol.
Thanks for the proofread! The red line slips by sometimes
If 'Correlation is not causation' confuses you, you should read up on the scientific method. I'll help you out getting started though:
There was a study done awhile ago that linked cannabis usage to heart disease. A group was found to have the symptoms / have died from conditions commonly associated with tobacco smoking. On the surface, this might lead one to believe you're facing the same dangers as tobacco when using cannabis.
The catch? The participants were also users of tobacco. There was no objective way to separate what cannabis caused and what tobacco caused, and yet this study was pointed to as 'evidence' of the dangers of cannabis.
Also regarding the 'However the risk is not possible to quantify.' bit : This is probably the biggest red flag. This means the people who carried out the study can't tell you how likely this is to happen. It could be 1/10 people, it could be more rare than getting struck by lightning twice.