Understanding Osteoporosis: Causes and Risk Factors

Osteoporosis is a common condition that weakens bones, making them fragile and more likely to break. It often develops slowly over several years and is frequently diagnosed only after a minor fall or sudden impact causes a fracture.

Osteoporosis affects over 200 million people worldwide. Although it can occur at any age, it is most common in older adults, particularly postmenopausal women. Around one in three women and one in five men over the age of 50 will experience an osteoporotic fracture in their lifetime.

Understanding the causes and risk factors of osteoporosis is essential to recognising its potential impact and taking steps towards prevention or early intervention.

What Is Osteoporosis?

Osteoporosis literally means ‘porous bones’ which occurs when the structure of bone tissue becomes less dense and more fragile over time. Healthy bone resembles a honeycomb under a microscope, but in osteoporosis, the holes and spaces in the honeycomb become larger, reducing the bone’s strength.

Bone is a living tissue that is constantly being broken down and rebuilt. This process, known as bone remodelling, ensures that bones remain strong and responsive to physical demands. During childhood and adolescence, bone formation happens more rapidly than breakdown, allowing bones to grow in size and density. Bone mass typically peaks in the late twenties, after which the balance gradually shifts towards bone loss.

In individuals with osteoporosis, the rate of bone loss exceeds the rate of new bone formation, resulting in bones that are thinner, weaker and more prone to fracture, particularly in the hips, spine and wrists.

There is no single cause of osteoporosis.

Osteoporosis is often called a ‘silent disease’ because it may not cause symptoms until a fracture occurs. In some cases, osteoporosis may be suspected based on a history of low-trauma fractures or signs of bone loss visible on routine imaging. However, bone mineral density (BMD) can be measured using a specialised X-ray scan, called a dual-energy X-ray absorptiometry (DEXA) scan, which provides a reliable assessment of bone strength.

Causes of Osteoporosis

There is no single cause of osteoporosis. Instead, it is the result of a combination of factors that influence bone strength over time. These include age-related changes in bone metabolism, hormonal fluctuations, certain medical conditions and lifestyle factors.

Ageing

Ageing is one of the most significant contributors to osteoporosis. As people grow older, the body’s ability to produce new bone slows down. Bone cells become less efficient, and calcium (an essential component of bone) is absorbed less effectively from the diet. This natural decline in bone density makes older individuals more susceptible to fractures, even with relatively minor injuries.

Hormonal changes

Hormones play an important role in maintaining bone health. Oestrogen, in particular, helps to protect bone by slowing the rate at which it is broken down. In women, oestrogen levels fall sharply after the menopause, leading to an accelerated loss of bone density. Men also experience a gradual decline in testosterone levels with age, which can affect bone strength, though typically to a lesser extent than in women.

Pre-existing medical conditions

Several underlying health conditions can contribute to the development of osteoporosis. These include:

• Rheumatoid arthritis - prolonged inflammation associated with certain autoimmune conditions that affect the joints can interfere with bone remodelling

• Coeliac disease - poor absorption of nutrients such as calcium and vitamin D can impair bone health

• Hyperthyroidism - excess thyroid hormones can increase the rate of bone turnover

• Chronic kidney disease - disruption of calcium and phosphate balance affects bone metabolism

Nutritional deficiencies

Bones require a steady supply of nutrients to maintain their strength. A diet low in calcium over the long term can lead to decreased bone density, while deficiency in vitamin D, which helps the body absorb calcium from food, can worsen this effect. Protein, magnesium and vitamin K also play supporting roles in maintaining bone integrity.

Risk Factors for Osteoporosis

While it may not cause noticeable symptoms in its early stages, knowledge of the underlying risk factors of osteoporosis can help individuals and healthcare professionals identify those who may be most at risk. These risk factors can be grouped into those that are non-modifiable (cannot be changed) and modifiable (related to lifestyle or environment).

Non-modifiable risk factors

Age

Risk increases with age, particularly after 50

Gender

Women are more likely to develop osteoporosis, especially post-menopause

Family history

A parental history of osteoporosis or hip fracture can indicate a genetic predisposition

Ethnicity

Individuals of Caucasian or Asian descent may be at higher risk

Body frame size

People with a small body frame generally have less bone mass as they age

Modifiable risk factors

Diet

Low intake of calcium, vitamin D, or overall poor nutrition can affect bone strength

Physical inactivity

Weight-bearing exercises, such as walking or resistance training, help maintain bone density; whereas a sedentary lifestyle increases risk

Smoking

Tobacco use interferes with bone remodelling and reduces calcium absorption

Alcohol consumption

Excessive alcohol intake can negatively affect bone formation and calcium balance

Medications

Prolonged use of certain drugs, such as corticosteroids or antiepileptics, can contribute to bone loss

Strong Bones, Stronger Future

Osteoporosis rarely announces itself loudly. It builds quietly over time, shaped by a subtle interplay of biology, lifestyle and environment. Yet this silence also offers an opportunity. The more we understand about what drives bone loss, the more power we have to intervene early and meaningfully.

Recognising risk factors is about awareness.

Looking ahead, prevention is not just a clinical goal, it is a personal one. Small, consistent choices made today, from nourishing the body well to staying active, can translate into stronger, more resilient years later. Recognising risk factors is about awareness. It allows individuals to take ownership of their bone health, making informed decisions that preserve mobility, independence and quality of life.

In many ways, bone health reflects how we care for ourselves over a lifetime. By paying attention now, we invest in a future where strength is not just maintained, but sustained with confidence.

---