The classmates of mine are all over 75 and we all liable to fall probably due to osteoporosis.  (A telltale sign myself: I have been at least 1 cm shorter in height than I was used to be.)  The symptom signifies our bones have become fragile, not that hard and strong when we were young.  Dear fellow seniors, be wary of your every "step" you are going to take.

PS Osteoporosis is a medical term which I think is not familiar to ordinary English-speaking people, but its Chinese translation "骨質疏鬆症" is understandable to almost every Chinese user.  So, which one is better, Chinese or English?