It would be helpful to hear more specific thoughts on whether / why this data is “garbage”.
An initial thought on that (since I don’t have time to dive deeper on this today) is that the first source linked in this post says most of the studies did not use a control group:
For the assessment of the quality of the included studies, we used the Newcastle-Ottawa Scale for observational studies.(22) Not every item from this scale was relevant for the included studies as most included studies did not use a control group. Therefore, we used two items from Selection (representativeness and ascertainment of outcome) and the three items from Outcome (assessment of outcome, follow-up long enough, adequacy of follow-up; see Supplementary Material).
It would be helpful to hear more specific thoughts on whether / why this data is “garbage”.
An initial thought on that (since I don’t have time to dive deeper on this today) is that the first source linked in this post says most of the studies did not use a control group: