Osteoporosis after menopause: the silent decade

What oestrogen was doing

Bone is continuously remodelled: osteoclasts break down old bone, osteoblasts build new. Through adult life the two are roughly balanced.

Oestrogen restrains osteoclast activity and supports osteoblast survival. When it falls, breakdown accelerates while building does not keep pace, and the balance tips into net loss.

The loss is front-loaded. The steepest decline occurs in the year before and the several years after the final period, with women losing up to a fifth of their bone density over five to seven years. After that the rate slows to a steadier age-related decline.

Why it is silent

Osteoporosis causes no pain, no stiffness and no warning. It is detected by scanning or by fracture, and in practice it is very often the second of those.

Vertebral compression fractures are the most common osteoporotic fracture and around two-thirds are never diagnosed, because they present as back pain after minimal force and are recorded as a strain.

Features suggesting one: sudden back pain after a sneeze or lifting, pain in the mid-back, pain much worse standing and relieved lying down, measurable height loss, or a developing stoop. Each fracture substantially raises the risk of the next, which is why identifying the first changes the trajectory.

Who should be assessed earlier

Fracture risk assessment tools combining age, weight, smoking, alcohol, steroid use, family history and previous fracture are used to decide who needs a bone density scan. Factors that raise priority:

• Menopause before 45, or surgical menopause before the natural age
• A previous fragility fracture — one from a fall from standing height or less
• Long-term oral corticosteroid use
• Parental history of hip fracture
• Low body weight, smoking, or high alcohol intake
• Coeliac disease, inflammatory bowel disease or other malabsorption
• Rheumatoid arthritis, or treatment with aromatase inhibitors after breast cancer

What acts on it

Mechanical loading is the stimulus bone responds to. The trial evidence for improving bone density in postmenopausal women comes predominantly from high-intensity resistance training and impact loading, not from light weights and high repetitions — which is the opposite of the advice usually given to midlife women.

Calcium and vitamin D are necessary but not sufficient; they support bone within requirements and do not by themselves prevent osteoporosis.

Hormone therapy prevents bone loss and reduces fracture risk, and it is specifically recommended for bone protection in women with early menopause or primary ovarian insufficiency. Specific bone medications exist for established osteoporosis and are a clinical decision.

Falls prevention deserves equal weight, because most fragility fractures happen in a fall. Balance training addresses the other half of the equation.

When to see someone

Ask for fracture risk assessment at a midlife review, and for a bone density scan if any of the risk factors above apply. This is rarely offered unprompted.

Seek prompt assessment for sudden back pain after minimal force, any fracture from a fall from standing height, or measurable height loss.