BOAS is related with brachycephalic breeds only because it is in the name (the first B). Per definition you cannot have BOAS as a Mesocephalic breed! Wouldn’t have been MOAS? But if you look at respatory upper problems in the next table you see the ranking of BOAS/respatory upper problems and you see the Affenpinscher on rank 77. So there are 76 (brachy?) breeds before the Affenpinscher. To be correct of course you have also other respatory upper deseases like kennel cough but it gives an indication.
Do you see the relationship?