I think there are a lot of factors to consider, but it does seem to be common. I'm 6'4, and I've had lower back problems for years, which goes back to getting hit from behind playing hockey (in a rec game without a referee or a scorekeeper -- I'm still quite sour about it).
I think posture has a lot to do with it, as I notice a lot of tall people with poor posture, and after spending the day having to bend over to use counters or tables, or ducking through doors, it can gradually do some damage. It's certainly preventable though. I don't believe all tall people are doomed to have back problems (unless you're an absolute giant like Shaq).