Final answer:
With aging, bone density peaks around age 30 and then declines, particularly in individuals with XX chromosomes post-menopause, leading to increased risk of osteoporosis. Exercise can increase bone thickness, while inactivity or weight loss can lead to bone thinning, which is also influenced by dietary changes.
Step-by-step explanation:
Changes in body composition and bone density are a natural part of aging. The process involves a variety of alterations in bone mass and muscle strength. Around the age of 30, peak bone mass is achieved; thereafter, a decline in bone density occurs, leading to conditions such as osteoporosis, especially in individuals with XX chromosomes following menopause due to decreased estrogen levels. Additionally, bones respond dynamically to changes in muscle strength and body weight.
A growth in muscle strength due to exercise, for example, leads to thickening at muscle attachment sites on bones. Conversely, reduced muscle strength or body weight, as seen during prolonged immobilization or in microgravity environments, can cause bone thinning. Changes in diet, like eating softer foods due to tooth loss, also affect bone thickness, specifically in the jawbones.