Which of these is/are true about osteoporosis?
1. It is the most common bone disease
2. Both males and females suffer from it
3. It involves a decrease in bone mass, especially in spongy bone
4. Risk factors include gender, age, smoking, poor nutrition, and sedentary lifestyle
a) 1 & 3
b) 2 & 4
c) 1, 2 & 3
d) 4 only
e) all of the above