Morgan Stanley have an interesting take on the economic effects of population ageing and in particular the lessons we can (and cannot) learn from Japan.
It is worth a read, unfortunately it is behind a paywall. Here is the link.
The bottom line of the argument is that we cannot learn much from Japan's experience because there were other factors that account for the length and depth of the Japanese recession.
Since most of the world is ageing at roughly the same rate (exclude Africa) the argument goes that labour will become scarce, wages will rise, tax take increases and we all live happily as older people spend their wealth on health care and modifying their properties.
Not sure I totally buy the arguments but neither do I agree with the proposition that ageing population = recession.
If you can I suggest reading the article. Dick Stroud