I know a recreational cyclist who did have problems because she was not getting enough impact. She was a long distance cycling junkie, about 5 days a week riding very long distances. But then again she may have had contributing factors. She is my mother's co-worker and is always advocating to my mom that I run. I do in the winter but in the hot months I mainly bike, some hiking. I agree with the quote, there is a probably a study to shoot this one down. I prefer mountain biking so I know there is more impact just riding than my road bike.

I still question if they are including risk factors in calculating this? Some people are going to be more likely to get osteoporosis for any number of reasons, not just because they are cyclists.