Why do old bones get fragile?

Several factors contribute to the fragility of old bones, often referred to as osteoporosis. Here are some key reasons why bones become weaker with age:

1. Decreased Bone Mass: Bone is a living tissue that constantly undergoes remodeling, where old bone tissue is broken down (resorption) and replaced with new bone tissue (formation). As we age, the balance between these processes shifts, with resorption outpacing formation. This results in a gradual loss of bone mass, leading to weaker and more fragile bones.

2. Hormonal Changes: Estrogen and testosterone, two hormones important for bone health, decline with age. Estrogen, particularly significant for women, plays a crucial role in maintaining bone density. After menopause, women experience a significant drop in estrogen levels, which accelerates bone loss. Men also experience a gradual decline in testosterone levels as they age, contributing to bone loss.

3. Reduced Calcium Absorption: Calcium is a mineral essential for bone formation and maintenance. However, the body's ability to absorb calcium from the diet decreases with age. This reduced absorption can lead to lower levels of calcium in the bones, making them more susceptible to weakening and fracture.

4. Vitamin D Deficiency: Vitamin D aids in the absorption of calcium. As people age, their skin becomes less efficient in producing vitamin D when exposed to sunlight. Additionally, many older adults have limited sun exposure due to reduced mobility or spending more time indoors. This can lead to vitamin D deficiency, further impairing calcium absorption and bone health.

5. Changes in Bone Microarchitecture: The internal structure of bones undergoes changes with aging. The honeycomb-like structure of bones becomes thinner and less dense, compromising their strength. This alteration in bone microarchitecture makes older bones more susceptible to fractures even with relatively low-impact trauma.

6. Lifestyle Factors: Certain lifestyle factors common in older age can contribute to bone fragility. These include physical inactivity, poor nutrition, smoking, and excessive alcohol consumption. Lack of regular weight-bearing exercise, an essential stimulus for bone formation, can accelerate bone loss. Smoking and alcohol can also hinder bone health by impairing bone formation and increasing the risk of falls.

It's important to note that osteoporosis is not an inevitable consequence of aging. By adopting a healthy lifestyle that includes regular exercise, a balanced diet rich in calcium and vitamin D, and avoiding harmful habits, individuals can help maintain strong bones and reduce the risk of fragility as they age.