It's all relative - the majority of women will end up with osteoporosis - stats from wikipedia:
Osteoporosis is a major public health threat which afflicts 55% of Americans aged 50 and above. Of these, approximately 80% are women.[90] It is estimated[citation needed] that 1 in 3 women and 1 in 12 men over the age of 50 worldwide have osteoporosis. It is responsible for millions of fractures annually, mostly involving the lumbar vertebrae, hip, and wrist. Fragility fractures of ribs are also common in men.

The only problem I have with osteopenia is that I don't think there's quite the data there to support everything that's being done - the definition of who has it vs. who doesn't, the data on what's normal bone loss over the years, since all women over 30 have thinning bones - vs. what's accelerated and will lead to osteoporosis. And the small machines they're using to diagnosis it checking peripheral bones instead of bone or hip...

So definitely, if someone's already broken bones - be concerned. If you have a family history of osteoporosis and they say osteopenia, be concerned... but if you don't have either of those, I'd say be concerned with a grain of salt, and up your calcium and weight bearing exercise - but I wouldn't necessarily start taking drugs for it until there's some more long term followup data and studies to support it. But - that's always a personal decision that everyone needs to research and decide on their own what's best for their bodies.