Bone health

Osteo = bone, necrosis = death, porosis= thin.

Are bone mineral changes a side effect?

HIV is one of several conditions that can reduce bone mineral density (BMD).

HIV in general reduces BMD a little more than natural ageing.

HIV treatment also reduces BMD a little but the benefits of ART generally outweigh this small risk in most people.

The SMART and START studies reported slightly lower bone density in people who were on any treatment, irrespective of which HIV meds were used.

Tenofovir DF can cause a small drop in bone mineral density .

Tenofovir DF can cause a small drop in bone mineral density. This is mainly in the first six months but this can continue.

Types of bone problems

There are two main types of bone problems.

1. Changes in content and structure of bone. This is where your bone becomes thinner and more brittle. This is called osteopenia at mild levels (when there are no symptoms) and osteoporosis at more severe levels (that require treatment).
2. Interruption of blood supply to the bone. This causes death of bone tissue – called osteonecrosis and avascular necrosis (AVN).

Osteopenia and osteoporosis

Rates of both osteopenia and osteoporosis are significantly higher in HIV positive people compared to the general population of the same age and sex.

It is still unclear if these higher rates are due to HIV or side effects or that bone health in the general population might be worse than older studies suggest.

Osteopenia is common and often doesn’t need treatment. Having osteopenia does not mean you will progress to osteoporosis.

Osteoporosis is more serious than osteopenia because it increases risk of fractures and pain (commonly to the spine in men and the hip in women).

In the general population, bone density keeps growing until about age 30 and then gradually reduces with age.

Risk factors for low bone mineral density (BMD) include:

• Age (bone density reduces in later life).
• Low body weight and low Body Mass Index (BMI) as heavier people have stronger bones.
• Lipodystrophy and metabolic changes (the way your body processes sugar and fat) are linked to bone changes.
• Use of corticosteroids (prednisone).
• Alcohol use (more than 3 units/day).
• Caucasian/Asian race.
• Smoking cigarettes.
• Low calcium or vitamin D levels.
• Lack of physical activity.
• Family history of osteoporosis.
• Low testosterone levels in men and early menopause in women.

Diagnosis: DEXA results

A DEXA scan is usually used to diagnose low bone mineral density.

Results are usually given as a T-score which compares your results to a reference group (age 30) matched for your sex and race.

A DEXA scan is recommended in some HIV guidelines for all post-menopausal women and for men older than 50 is recommended.

Osteonecrosis and avascular necrosis

Osteonecrosis and AVN are luckily less common. They usually affect the hip, shoulder or knee joints, and requires replacement surgery.

Corticosteroid use is a common factor in cases of AVN.

Early diagnosis of AVN makes a big difference to the success of treatment as well as your quality of life. If you have pain in these joints, ask to see a specialist. An MRI scan is used to make an appropriate diagnosis.

Protecting bones: treatment and prevention

Your bones are a living structure, 10% of which naturally die each year to be replaced by new cells. Your bones become thinner and more brittle if the bone isn’t replaced quickly enough or in sufficient quantities.

Leading an active life, and regular exercise, maintains healthy bone. This includes weight-bearing exercise (walking, jogging, running, steps and dancing) and muscle strengthening exercise. Improvements include better posture, balance and strength and a direct improvement in bone density.

If you have osteoporosis some common exercises, including twisting and stretching might not be recommended. Take expert advice.

Treatment and prevention measures are similar to HIV negative people – although closer monitoring of HIV positive people is important.

Stopping smoking, drinking less alcohol, taking exercise and eating a diet adequate in calcium, protein and vitamin D (and spending some time in the sun) protect you against bone mineral loss.

Bone-building nutrients include calcium and vitamin D₃ (cholecalciferol) and any deficiency should be corrected by increasing dietary intake or use of supplements.

Guidelines recommend adult targets using 1200 mg daily for calcium and 800 -1000 IU/day for vitamin D₃ (for people at higher risk).  If you have very low levels (<15 nmol/L) then use higher doses (50,000 IU weekly) for the first few months.

These nutrients can be prescribed by your doctor and sometimes require special monitoring and dosing.

The target for vitamin D is for blood levels of 25(OH)D to be higher than 75 nmol/L.

Although HIV meds might have a small negative impact on bone strength, the other benefits of treatment usually outweigh this small risk.

First-line medications to improve bone mineral density are a family of drugs called bisphosphonates. These include alendronate (Fosamax), risedronate (Actonel) as first-line treatment and zoledronate (Zometa). These might only be needed for a few years until a treatment response is achieved.

Second-line and alternatives include denosumab (Prolia) and teriparitide (Forsteo).

Links

• National Osteoporosis Society (UK)
• National Osteoporosis Society osteoporosis drugs information page
• Bone Research Society
• National Osteoporosis Foundation (US)

Last updated: 1 March 2023.