Osteoporosis is a condition where bones become weak and are more likely to fracture. It mainly happens because of a decrease in bone mineral density. There are many reasons for osteoporosis, the most common being aging, especially in women after menopause. Other factors include a lack of calcium and vitamin D intake, lack of exercise, smoking and excessive alcohol consumption, use of certain medications, and family history. Preventive methods include a balanced diet rich in calcium and vitamin D, regular exercise, avoiding smoking and limiting alcohol, and regular bone density tests.