Louisiana State University at Baton Rouge is currently conducting a bone-density study on male caucasian cyclists over 40 years old. I participated (free bone scan result = no osteoporosis risk for me).

Osteoporosis comments from my doctor: The best predictor of osteoporosis in older adults is the calcium consumption in childhood. From childhood up to 20 years of age, bones are somewhat flexible and are still in development. From the age of 20 onward, calcium intake is for "maintenance" only, and can't replace what was missed in earlier life (regardless of HOW MUCH you consume). Good childhood nutrition (including a calcium-rich diet) = lower risk of osteoporosis, period.

I take three calcium pills per week just to keep my wife happy, but they may just be cosmetic. Cheers!