Which lifestyle factor increases the risk of osteoporosis?

• A. Low physical activity
• B. High physical activity
• C. Regular sunlight exposure
• D. High calcium intake

Answer: (A)

The amount of mechanical load on bone from physical activity drives bone remodeling. When activity is low, the stimulus that tells bone to form is reduced, so bone resorption can exceed formation, leading to decreased bone density over time and a higher risk of osteoporosis. In contrast, weight-bearing and resistance exercises help maintain or increase bone density by providing the needed stress that stimulates osteoblast activity. Regular sunlight exposure and adequate calcium intake support bone health by ensuring vitamin D synthesis and calcium availability, and higher physical activity generally protects against osteoporosis. So, the lifestyle factor that increases risk is low physical activity.