Postmenopausal osteoporosis: causes, scans and treatment

Bone is renewed throughout life, and oestrogen helps the balance tip in favour of keeping it. The NHS explains that oestrogen is essential for healthy bones and that, after the menopause, falling oestrogen can lead to a rapid decrease in bone density. This is why women are more at risk of osteoporosis than men, and why the first few years after the menopause are when bone is lost most quickly.

Osteoporosis itself does not hurt. The NHS says it is not usually painful until a bone is broken, and that the most common injuries are to the wrist, hip and the vertebrae of the spine. A cough or sneeze can occasionally cause a broken rib or partial collapse of a spinal bone, and spinal fractures are a common cause of long-term pain and of a stooped posture.

The NHS identifies several situations that raise the risk beyond ordinary postmenopausal bone loss. Women are at greater risk of osteoporosis if they have:

• an early menopause, before the age of 45

• a hysterectomy before 45, particularly when the ovaries were removed too

• absent periods for more than 6 months as a result of over-exercising or too much dieting

• a family history of osteoporosis, in particular a parent who broke a hip

• a body mass index of 19 or less, or a history of an eating disorder

• long-term use of high-dose steroid tablets, rheumatoid arthritis, or malabsorption problems such as coeliac disease and Crohn's disease

• hormone-lowering medicines used to treat breast cancer, or long periods of inactivity such as extended bed rest

NICE Clinical Knowledge Summaries describe a risk-first approach. A 10-year fracture risk is calculated with QFracture or FRAX, and that score guides whether a bone density scan or treatment is needed. People at high risk are offered a scan to confirm osteoporosis; people at low risk are not offered treatment or a scan and receive lifestyle advice. People over 50 who have had a fragility fracture should be offered a scan, and a bisphosphonate should be offered to those with a T-score of -2.5 or lower if appropriate and there are no contraindications.

The scan is a DEXA bone density test. The NHS describes it as a quick, painless procedure of 10 to 20 minutes, using a much lower radiation dose than a standard X-ray. Your result is compared with a healthy young adult and expressed as a T-score: above -1 is normal, between -1 and -2.5 is osteopenia, and below -2.5 is osteoporosis. Scans are not recommended in pregnancy.

CKS also advises looking for other causes of weak bones where appropriate, such as an overactive thyroid, because these can be treated in their own right.

The NHS sets out a range of treatments. Which is chosen depends on age, risk, bone density results and other health conditions.

Bisphosphonates are the most common starting point, and how they are taken matters. The NHS advises taking them on an empty stomach with a full glass of water, then standing or sitting upright for 30 minutes and waiting between 30 minutes and 2 hours before eating or drinking anything else. Calcium and vitamin D supplements are taken at a different time of day.

The main side effects the NHS lists are irritation of the food pipe, swallowing problems and stomach pain. Osteonecrosis of the jaw, where jaw bone cells die and healing is affected, is rare and is linked mostly with high-dose intravenous treatment for cancer rather than osteoporosis; people with a history of dental problems may be advised to have a check-up before starting. NICE CKS says follow-up should check for side effects, adherence and whether treatment should continue after 5 years.

HRT is mainly taken to control menopause symptoms, but the NHS says it also keeps bones strong and reduces the risk of osteoporosis, and that if you already have osteoporosis it can strengthen your bones and reduce the chance of a fracture. NICE CKS notes it can be considered in younger postmenopausal women to reduce fracture risk while relieving menopausal symptoms.

The risks and benefits depend on your age and circumstances. The NHS says some types of HRT slightly increase the risk of breast cancer, particularly with long-term use, and that HRT tablets (but not patches, gel or spray) slightly increase the risk of blood clots. For women aged 60 or under with menopause symptoms, the benefits will usually outweigh the risks. If periods stop before 45, women are usually advised to take HRT or a hormonal contraceptive until at least 51, to protect against osteoporosis and other conditions.

NICE guidance on menopause also recommends that bone health is discussed with people going through menopause, and that they are told about the importance of keeping muscle mass and strength through physical activity.

Having osteoporosis does not mean a fracture is certain. The NHS suggests checking the home for trip hazards such as trailing wires and loose rugs, using rubber mats by the sink and in the bath, and having regular sight and hearing tests. Some older people are advised to wear hip protectors.

If you are over 50 and have broken a bone, a fracture liaison service can help prevent further breaks. The NHS adds that osteoporosis does not slow the healing of a broken bone, though a complicated wrist or hip fracture may need an operation. The Royal Osteoporosis Society runs a nurse-led helpline and local support groups for people who are newly diagnosed.