I think you're referring to the Canadian and Mexican studies that were excluded from the meta-analysis.
If you read the paper, two Canadian studies and three Mexican studies were excluded, but not all of them were. Table 3 only shows results from studies that were judged to be robust.
If you read the paper, two Canadian studies and three Mexican studies were excluded, but not all of them were. Table 3 only shows results from studies that were judged to be robust.