Osteoporosis is a disease where bone density decreases, making bones more brittle and prone to fractures. It is caused by age-related reduction in calcium and vitamin D, lack of exercise, smoking, alcohol, genetics, and other medical conditions. Many people experience no symptoms initially, but later can have bone pain, fractures, or stooped posture. Treatment focuses on lifestyle changes like exercise and diet, along with medications to strengthen bones and reduce pain as recommended by a doctor. Preventing osteoporosis requires quitting smoking, limiting alcohol, preventing falls, and maintaining good nutrition.