Osteoporosis is due to a reduction in bone density that makes bones more likely to fracture. Peak bone mass in men and women is achieved in the third decade of life and is followed by gradual age-related bone loss in both sexes. There’s an increase in bone loss following the menopause, so post-menopausal women are at much greater risk of osteoporosis than men. In osteopenia, the bone density is below average for that age but isn’t low enough to be classed as osteoporosis.

This article was included in issue 99 (Winter 2023-24) of The Menopause Exchange newsletter

About osteoporosis
Osteoporosis doesn’t cause any symptoms but can lead to an increased risk of fractures. The three most common sites are the wrist, the vertebral spine, and the hip.
Wrist (Colle’s) fractures usually result from falling on an outstretched hand. These don’t usually need hospital admission, and the recovery is usually complete.
Spinal (vertebral) fractures are the most common fractures. These may not cause any symptoms but can sometimes result in a loss of height, curvature of the spine or back pain. It’s estimated that 70% of vertebral fractures don’t come to medical attention.
Hip (proximal femur) fractures are more serious. These tend to occur in older women and are associated with significant morbidity and mortality. About 10% of patients will die within one month of injury, and about one third within 12 months. Around 50% of those who survive this injury don’t regain their pre-injury mobility.

Diagnosis
Osteoporosis is diagnosed using a bone density (DEXA) scan, which uses low levels of X-ray and is quick and safe. While it’s not cost effective to screen the whole population for osteoporosis, women who are at increased risk should have a DEXA scan. The bone density measurement is usually expressed as the T- score. A T score of between -1.0 and -2.5 is defined as osteopenia; in osteoporosis, the T score is less than -2.5. DEXA scans are also useful in monitoring osteoporosis treatment.

Risk factors for osteoporosis include:

• Caucasian race
• having had a previous fracture
• having a premature menopause
• having never given birth
• a history of anorexia or exercise-related amenorrhoea (having no periods)
• a family history of osteoporosis
• steroid use
• excess consumption of alcohol or caffeine
• an overactive thyroid (thyrotoxicosis)

Hormone replacement therapy
HRT is the first-line management approach in the prevention and treatment of postmenopausal osteoporosis. Oestrogen replacement can prevent bone loss as well as reverse it, and has been shown to reduce the incidence of fractures.

HRT can ease menopausal symptoms such as hot flushes, night sweats, poor sleep, tiredness, mood swings and forgetfulness, improving quality of life. However, unfounded concerns remain about its safety, largely based on the flawed WHI studies. Current evidence indicates that the long-term use of HRT is associated with a reduced risk of heart disease and together with the prevention of osteoporosis means that women on HRT tend to live longer and healthier lives.

Women who have a premature menopause (before the age of 40), also known as premature ovarian insufficiency, are at increased risk of osteoporosis because they start losing bone density at a younger age. It’s especially important for these women to be offered HRT to protect against osteoporosis as well as other long-term effects of the menopause, including heart disease and possibly dementia. HRT will also prevent menopausal symptoms, which can be particularly distressing in these young women.

Rapid or severe weight loss and excessive exercise can cause the ovaries to stop working and the menstrual cycle to stop. The resultant loss of oestrogen production can lead to bone loss and osteoporosis. These women are at increased risk of post-menopausal osteoporosis because they will already have some reduction in bone density, even before the menopause. They should be offered advice and support to make the necessary lifestyle changes that can result in the return of ovarian function and bone mass, but they can also use oestrogen treatment.

Non-hormonal treatment
Regular exercise and a healthy diet with adequate calcium and vitamin D intake are important in maintaining bone density. This lifestyle helps to reduce the risk of developing osteoporosis but has very little impact in established osteoporosis.

Selective Estrogen Receptor Modulators (SERMS), such as raloxifene, act as oestrogens in some tissues, such as bones, and as anti-oestrogens in other tissues, such as the breast. These medicines are less effective than oestrogen in preventing osteoporosis. SERMS have been shown to reduce the risk of vertebral fractures but not hip fractures and they don’t ease menopausal symptoms.

Bisphosphonates can be used in the treatment of osteoporosis and have been shown to reduce the incidence of osteoporotic fractures. However, their prolonged use may result in fragility fractures in the femur (thigh bone) and osteonecrosis (poor blood supply leading to bone death) in the jaw, particularly following dental treatment such as dental extraction. Bisphosphonates can persist in bones for many years so aren’t recommended in younger post-menopausal women.

Denosumab can increase bone density and reduce the risk of fractures at the spine and hip but has similar side effects to bisphosphonates. Moreover, this medicine can affect the immune system, with an increased risk of infections.

About the author

Mr Mike Savvas is a consultant gynaecologist with a specialist interest in the menopause. He retired from his NHS role at King’s College London in 2023 and now works at the London PMS and Menopause Centre.

Created Winter 2023-24
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