I would like to know if others in this group are aware of the problem
with pop top canned cat foods and the onset of hyperthyroidism in
cats.  The problem is apparently caused by an ingredient that is a
coating in these cans called bisphenol A.   A study was conducted in
the J. of the American Vet Association; the results of which indicated
the following (J Am Vet Med Assoc. 2004 Mar 15;224(6):879-86):

RESULTS: Age-specific hospital prevalence of feline hyperthyroidism
increased significantly from 1978 to 1997. Overall, consumption of
pop-top canned (vs dry) food at various times throughout life and each
additional year of age were associated with greater risk of developing
hyperthyroidism. In female cats, increased risk was associated with
consumption of food packaged in pop-top cans or in combinations of
pop-top and non-pop-top cans. In male cats, increased risk was
associated with consumption of food packaged in pop-top cans and age.
CONCLUSIONS AND CLINICAL RELEVANCE: These findings suggest that the
increasing prevalence of feline hyperthyroidism is not solely the
result of aging of the cat population and that canned foods may play a
role.

I wonder how much the cat food companies are considering this as a
problem.  I, for one, would not have a problem with going back to
opeining canned foods with the appropriate instrument if it would
eliminate this problem.  I have also raised my two cats on wet foods
for their whole lives and would hate to switch them to dry now.

I would like opinions on those who are in the know on this matter.

Thanks,  Al