Bone Loss in the Menopause

When does it happen, and how fast?

Bone loss does not begin after the menopause but about a year before the last period. The figures from the SWAN study are:

• The transition (from 1 year before to 2 years after the last period) — the fastest phase: 2.46% a year at the spine and 1.76% a year at the hip.
• Total loss over those three years: an average of 10.6% at the spine and 9.1% at the femoral neck.
• Afterwards (2-5 years after the last period): the rate slows but does not stop — roughly 1% a year at both sites.

Who is at higher risk?

Factors that cannot be changed

• Older age
• Family history of osteoporosis; a hip fracture in a parent
• Having had a fracture after only a minor knock

Factors that can be changed

• Loss of more than 3 cm in height — this can indicate a silent vertebral collapse
• Frequent falls, poor balance, loss of muscle mass
• Inactivity
• Low body weight (body mass index below 18)
• Vitamin D deficiency; a diet low in calcium and protein
• Smoking; more than 2 standard drinks of alcohol a day

Some medicines also accelerate bone loss directly — corticosteroids, certain medicines that reduce stomach acid, and some medicines used in breast cancer treatment. Tell your doctor about any medicines you take regularly.

Who should have a bone density scan?

A bone density scan (DEXA) is not a test everyone should have; risk is assessed first.

• Aged 65 and over: a scan is recommended if never done before, even without additional risk factors.
• Under 65: rather than scanning directly, the 10-year fracture probability is first calculated with a tool such as FRAX; a scan follows if risk is identified.

How often is it repeated?

• If the result is normal and hormone therapy is being maintained, there is little value in repeating within 5 years.
• If low bone mass is found, or rapid loss is expected, it is repeated every 1-3 years.

Calcium, vitamin D and exercise

Calcium: the daily target after the menopause is 1000-1200 mg, and it should come primarily from food — 3-4 servings a day of milk, yoghurt or cheese. Supplements should be used selectively, only when intake from food is insufficient: routine calcium supplementation in low-risk women has been shown to increase the risk of kidney stones.

Vitamin D: the daily target is 800-1000 IU. While 20 ng/dL is generally accepted as the blood threshold, above 30 ng/dL is recommended for bone health. The amount right for you is set according to your blood level.

Exercise: at least 150 minutes of moderate activity a week, plus two resistance sessions. There is an important nuance here: in established bone loss, the main benefit of exercise is not increasing bone mass but improving muscle strength and balance so as to prevent falls and fractures. The programme must be built for the individual; a poorly planned one can increase the risk of falling.

In early menopause

Loss of ovarian function before 40, or menopause before 45, affects bone much earlier and much harder:

• In early menopause the overall fracture risk rises by about 36%, and the risk of fragility fracture by 48%.
• In women who reach the menopause at 45 or younger, the 10-year hip fracture risk has been found 1.6 times that of their peers.
• In this group, stopping hormone therapy triggers a wave of rapid loss at the femoral neck.

For that reason, guidelines make a strong recommendation that women with early menopause receive hormone therapy until the usual age of the menopause (around 50) — even without symptoms.

The place of hormone therapy in bone health

Hormone therapy is the first-line option for preventing menopause-related bone loss and significantly reduces fracture risk. The balance of benefit and risk is most favourable when it is started within 10 years of the menopause or before the age of 60. Bone loss accelerates again when treatment stops.

Where bone loss is established there are also prescription treatments; which is appropriate is decided by specialist assessment according to fracture risk. For all the screening tests see menopoz check-up.