Very interesting info. As any medic/scientist would tell you, the reason for a lack of scientific evidence showing a link is due to a lack of good studies, and the inability to get reliable results because of the number of factors involved.
The same is true of many areas of medicine where using the categories of evidence based medicine, sometimes a really critical medical question can only be addressed through one of the lower categories, that is expert opinion. I have a feeling that the ensuing court cases will hinge on a lot of 'expert opinion' due to the lack of good (type 1/2) evidence.
My question is : Who funds the Aerospace Medical Association? (rhetorical)