Why does bone density typically decrease later in adulthood?

• A. People typically eat less calcium and vitamin D as they age.
• B. During remodeling, cells that deposit bone tend to be less active than those that remove bone as people age.
• C. Bone remodeling naturally tends to remove more bone than it deposits and bone remodeling does not begin until growth is complete.
• D. As we age, bone remodeling tends to replace cortical bone with trabecular bone, which is less dense.

Answer: (B)

Verified step by step guidance

1. Understand the concept of bone remodeling: Bone remodeling is a natural process where old bone tissue is replaced with new bone tissue. This involves two types of cells: osteoblasts (which deposit bone) and osteoclasts (which remove bone).
2. Recognize the age-related changes in bone remodeling: As people age, osteoblast activity (bone deposition) tends to decrease, while osteoclast activity (bone removal) remains active or increases. This imbalance leads to a net loss of bone density.
3. Learn about the types of bone affected: Cortical bone (dense outer layer) is often replaced with trabecular bone (spongy inner layer) during aging. Trabecular bone is less dense and contributes to the overall decrease in bone density.
4. Consider the role of nutrients: Calcium and vitamin D are essential for maintaining bone health. As people age, dietary intake of these nutrients often decreases, further contributing to reduced bone density.
5. Understand the timing of bone remodeling: Bone remodeling begins after growth is complete and continues throughout life. However, the imbalance between bone deposition and removal becomes more pronounced with age, leading to decreased bone density.