Paediatric Osteoporosis

See also lower limb developmental problems (which includes club foot/talipes) for other paediatric MSK presentations, and adult osteoporosis — a substantially different diagnostic framework (T-scores, fragility fracture thresholds) that does not apply to children.

About half of all children sustain at least one fracture before adulthood, and roughly 1 in 5 fracture more than once — most from ordinary falls and sport. The central clinical challenge is distinguishing these otherwise healthy children from the minority with a genuine bone fragility disorder, without either over-diagnosing “osteoporosis” in a child who was simply unlucky, or missing a serious underlying condition. Childhood bone fragility differs from the adult disease in a critical way: a growing skeleton can often reclaim lost bone density and reshape collapsed vertebrae without any drug treatment, provided the underlying threat to bone health resolves and there is enough residual growth left to do it.

Diagnostic criteria

Densitometry (BMD) alone should never be used to diagnose osteoporosis in a child. The 2019 ISCD Official Pediatric Positions define osteoporosis in children and adolescents as either:

• ≥1 vertebral compression (crush) fracture, in the absence of local disease or high-energy trauma — diagnostic on its own, regardless of BMD; or
• In the absence of a vertebral fracture, both of the following: a clinically significant fracture history (≥2 long-bone fractures by age 10, or ≥3 long-bone fractures by age 19) and a BMD Z-score ≤ -2.0.

A BMD Z-score above -2.0 does not rule out skeletal fragility — it simply means the criteria for a formal diagnosis of osteoporosis are not yet met on densitometry grounds. Low-trauma is defined as a fall from standing height or less, at no more than walking speed (a more conservative threshold than the general paediatric definition of a fall from ≤3 metres, reflecting the higher background fracture risk in chronic illness).

Terminology rules specific to children: T-scores and the term “osteopenia” should never appear on a paediatric DXA report. “Low bone mineral mass or density” is the preferred term when the Z-score is ≤ -2.0 but the fracture criteria for osteoporosis aren’t met, and “osteoporosis” itself should not appear on a report without an accompanying clinically significant fracture history.

Step 1: rule out rickets and non-accidental injury first

Any child referred with bone fragility should have an initial biochemical screen — serum calcium, phosphate, creatinine, alkaline phosphatase, PTH and 25-hydroxyvitamin D, plus urinary calcium, phosphate and creatinine — to exclude rickets (which can cause or compound fracture risk in its own right). Rib and scapula “pseudofractures” (Looser zones) are typical of rickets/osteomalacia; once these are excluded, flat-bone fractures (skull, rib, scapula, sternum) without a clear history of significant trauma are a red flag for non-accidental injury rather than metabolic bone disease.

Other NAI red flags: delayed presentation, unexplained bruising or other injury signs, multiple fractures at different healing stages, a fracture inconsistent with the reported mechanism, and the absence of physical stigmata of a congenital bone fragility disorder despite a significant fracture. Note the two diagnoses are not mutually exclusive — maltreatment can occasionally unmask an underlying bone fragility condition, and a genuine monogenic disorder can be misattributed as NAI — so a low threshold for genetic/specialist input is recommended whenever a child is referred under a child-protection framework with an unclear fracture mechanism.

Primary vs secondary osteoporosis

Once rickets and NAI are excluded, the next step is distinguishing congenital (primary) bone fragility from an acquired (secondary) cause.

Primary osteoporosis (congenital)	Secondary osteoporosis (acute/chronic illness)
Osteogenesis imperfecta (most common — a type I collagen disorder; look for blue sclerae, dentinogenesis imperfecta, joint hypermobility, short stature, family history — though mild forms can lack all of these) Other monogenic disorders (e.g. LRP5-related bone fragility) presenting with fractures but no classic OI stigmata	Prolonged glucocorticoid therapy (any indication) Neuromuscular disease with reduced mobility/weight-bearing (e.g. Duchenne muscular dystrophy, cerebral palsy) Haematological malignancy, especially acute lymphoblastic leukaemia Chronic inflammatory disease — inflammatory bowel disease, juvenile idiopathic arthritis Prolonged immobilisation Poorly controlled chronic illness generally

A single long-bone fracture can itself represent a major osteoporotic event in a child with one of these risk factors, or with a first presentation of a skeletal dysplasia — the bar for triggering a bone health work-up is much lower here than for an otherwise well child. Conversely, in a child with no risk factors and no stigmata, recurrent forearm fractures specifically (the single most common paediatric fracture site) are usually needed before a comprehensive evaluation is warranted, since isolated forearm fractures are extremely common in healthy, active children. Femur, humerus and tibia fractures are more concerning even in isolation. A low-trauma vertebral fracture is always significant and warrants specialist evaluation — it occurs in around three-quarters of children with even mild osteogenesis imperfecta, and in a third of children with leukaemia within six years of diagnosis.

Bone health assessment (specialist-led)

DXA is the standard tool, with posterior-anterior spine and total-body- less-head the preferred sites in most children. Z-scores need adjustment for height in children with short stature or growth delay, since areal BMD by DXA is otherwise artificially lowered by small bone size alone. A follow-up scan should not be repeated less than 6–12 months after the last one. Genetic testing and detailed skeletal phenotyping (lateral spine imaging for vertebral fracture assessment, skeletal survey where a dysplasia is suspected) are the domain of a paediatric bone health/endocrinology service, not primary care.

Management principles

Because the growing skeleton can spontaneously recover, not every child who meets osteoporosis criteria needs drug treatment. Factors favouring watchful monitoring over treatment include younger age, transient risk factors (e.g. a short glucocorticoid course, brief immobilisation of under 2 weeks, a well-controlled underlying illness), and milder vertebral collapse. Factors favouring treatment include older age, persistent risk factors (ongoing glucocorticoids, sub-normal mobility, poorly controlled disease, or a primary/genetic diagnosis), and more severe vertebral collapse.

Where treatment is warranted, intravenous bisphosphonate therapy (pamidronate or zoledronic acid) is the specialist standard of care, started and monitored only by clinicians experienced in paediatric bone health — this is not something initiated in general practice. Children with primary osteoporosis are typically treated until epiphyseal fusion; those with secondary osteoporosis, until their risk factors resolve.

The GP’s role

• Recognise the at-risk groups above (especially children on prolonged glucocorticoids, with reduced mobility, or with a chronic inflammatory or haematological illness) and refer for a bone health assessment proactively — don’t wait for a fracture to occur first.
• Don’t over-interpret an isolated fracture in an otherwise healthy, active child with no risk factors — most childhood fractures, including recurrent forearm fractures, do not indicate osteoporosis.
• Ensure adequate vitamin D and calcium intake, and encourage weight-bearing physical activity where the child’s underlying condition allows it — both support bone mass accrual during the window when it matters most.
• If a DXA report is seen in general practice, understand that a T-score or the word “osteopenia” should never appear on a paediatric report, and that “osteoporosis” alone (without a supporting fracture history) is not a valid diagnosis on densitometry grounds alone.