There was no actual mention of a lack of offered treatment in the OP. It was implied but not stated. I don't think we have all the necessary information because the OP just fired off a rant about ageism.
I've known doctors say similar things about age-related health problems (for young children, for teenagers, for women during their fertile years, and for post-menopausal women) and then explain what treatment is available and/or what one can do to help oneself. They are giving information both when they comment on age-relatedness and when they explain treatment (if there is any).
If the OP was actually "fobbed off" with what she calls an ageist comment then she should be complaining to the practice and higher rather than on Gransnet. Well... maybe as well as on Gransnet.
But until she states categorically that she was offered no help whatsoever (advice counts just as much as a prescription), then I don't accept that the doc was necessarily being ageist.