Common risk factors for osteoporosis and fractures in men include:

• A fracture (a broken bone) which resulted from a minor fall or bump
• A family history of osteoporosis and fractures (e.g. a parent who suffered a hip fracture)
• Crohns disease or celiac disease
• Vitamin D deficiency
• Rheumatoid arthritis
• Low sex hormone levels (i.e. testosterone)
• Excessive alcohol intake (i.e. more than two 120 ml glasses of wine per day)
• Smoking
• Being underweight

The National Osteoporosis Foundation in the United States provides a useful overview of risk factors.