When to Suspect Osteoporosis in Children and Adolescents
Osteoporosis in children and adolescents should be suspected when there is a low-trauma vertebral compression fracture (even a single one), OR when there are two or more long bone fractures of the lower extremities, OR when there is low bone mineral density (Z-score ≤ -2.0) combined with a clinically significant fracture history. 1
Clinical Scenarios Requiring High Suspicion
Primary Risk Factors for Screening
Chronic glucocorticoid therapy (≥6 months) is the most common acquired cause requiring bone health surveillance, as steroids directly impair bone formation and increase fracture risk. 2, 3
Prolonged immobilization from conditions like cerebral palsy, Duchenne muscular dystrophy, or spinal cord injury creates severe bone loss through mechanical unloading. 2, 3
Chronic diseases including inflammatory bowel disease, cystic fibrosis, chronic kidney disease, rheumatoid arthritis, and malignancies with chemotherapy exposure all compromise bone accrual during critical growth periods. 1, 3
Endocrine disorders such as hypogonadism, growth hormone deficiency, hyperthyroidism, and Cushing syndrome directly impair peak bone mass attainment. 2, 4
Nutritional deficiencies particularly in eating disorders, malabsorption syndromes, or functional hypothalamic amenorrhea in female athletes with low energy availability. 1
Specific Red Flags in History
Menstrual dysfunction in adolescent females—delayed menarche (>15 years), amenorrhea, or oligomenorrhea (≤6-8 menses per year)—strongly predicts compromised bone health. 1
Low body mass index (<17.5-18.5 kg/m²) or recent weight loss (5-10% in one month) indicates inadequate energy availability affecting bone metabolism. 1
Recurrent low-trauma fractures especially of vertebrae, long bones of lower extremities, or multiple upper extremity fractures warrant immediate evaluation. 1, 2
Medications including depot medroxyprogesterone acetate, anticonvulsants, chronic heparin, androgen deprivation therapy, or aromatase inhibitors for ≥6 months. 1
Family history of early-onset osteoporosis or genetic bone disorders (osteogenesis imperfecta, hypophosphatasia) suggests inherited bone fragility. 2, 5
How to Diagnose Osteoporosis in Children and Adolescents
Diagnostic Criteria: The Critical Distinction
The diagnosis of osteoporosis in children and adolescents CANNOT be made on bone mineral density alone—it requires BOTH low BMD (Z-score ≤ -2.0) AND a clinically significant fracture history. 1
Exception to the Rule
A single low-trauma vertebral compression fracture alone is sufficient to diagnose osteoporosis, regardless of BMD. 1, 5
Clinically Significant Fracture History Defined
- One or more vertebral compression fractures 1
- One long bone fracture of the lower extremities (femur, tibia excluding ankle) 1
- Two or more long bone fractures of the upper extremities 1
Important Caveat
A Z-score > -2.0 does NOT exclude osteoporosis if there are vertebral fractures or multiple low-trauma long bone fractures in the appropriate clinical context (e.g., chronic steroid use, immobilization). 1, 5
DXA Imaging: Technical Requirements
Which Sites to Measure
For children and adolescents <20 years:
- Posteroanterior lumbar spine (L1-L4) for bone mineral content (BMC) and areal BMD 1
- Whole body less head (or whole body if unavailable) for BMC and areal BMD 1
- Lateral distal femur when other sites are not measurable (e.g., severe contractures, hardware) 1
Do NOT measure hip/femoral neck in growing children as reference data are less reliable and interpretation is problematic during growth. 1
Critical Adjustments Required
In children with short stature or growth delay, BMD MUST be adjusted:
- For spine: Use bone mineral apparent density (BMAD) or height Z-score adjustment 1
- For total body less head: Adjust using height Z-score 1
- Use pediatric reference data specific to age, sex, and ethnicity 1
Failure to adjust for body size leads to overdiagnosis of osteoporosis in constitutionally small children. 1, 5
Scoring System: Z-Scores NOT T-Scores
Always use Z-scores (age- and sex-matched) in children, adolescents, premenopausal women, and men <50 years. 1
NEVER use T-scores or WHO criteria (T-score ≤ -2.5) in pediatric populations—this is a critical error that leads to misdiagnosis. 1, 6
Z-score ≤ -2.0 = "bone mineral density below the expected range for age" (avoid terms "osteopenia" or "osteoporosis" based on BMD alone). 1
When to Perform DXA Screening
High-risk indications for baseline DXA:
- Chronic glucocorticoid therapy ≥3 months (or anticipated ≥3 months) 2, 3
- History of low-trauma vertebral or long bone fracture 1
- Chronic disease with known bone fragility risk (see above) 3
- Prolonged immobilization or non-ambulatory status 2, 3
- Delayed puberty, amenorrhea >6 months, or eating disorder 1
Repeat DXA frequency:
- Every 6-12 months in high-risk patients on treatment or with ongoing risk factors 1, 3
- After at least 1 year interval to detect meaningful change (must exceed least significant change of ~3-5%) 1
Laboratory Evaluation: Identifying Secondary Causes
Essential Initial Workup
Complete blood count to screen for anemia, malignancy, or chronic inflammation. 2
Comprehensive metabolic panel including calcium, phosphate, alkaline phosphatase, creatinine, and liver function tests. 2
25-hydroxyvitamin D level (target >30 ng/mL; deficiency <20 ng/mL impairs bone mineralization). 2, 3
Parathyroid hormone (PTH) to assess for primary or secondary hyperparathyroidism. 2
Thyroid function tests (TSH, free T4) as hyperthyroidism accelerates bone turnover. 2
Endocrine Assessment in Appropriate Contexts
In females with menstrual irregularities:
- Luteinizing hormone (LH), follicle-stimulating hormone (FSH), estradiol 1
- Pregnancy test (β-hCG) 1
- Prolactin if amenorrhea present 1
In males with delayed puberty or hypogonadism:
- Total testosterone, LH, FSH 2
If growth delay or short stature:
- Insulin-like growth factor 1 (IGF-1), IGF binding protein 3 2
- Consider growth hormone stimulation testing 2
Bone Turnover Markers (Optional)
Serum procollagen type I N-propeptide (P1NP) for bone formation and serum C-terminal telopeptide of type I collagen (CTX) for bone resorption can assess bone metabolism, though interpretation is challenging due to age-related variability. 1
These markers are NOT required for diagnosis but may help monitor treatment response. 1
Genetic Testing When Indicated
Consider genetic evaluation if:
- Multiple vertebral fractures with minimal trauma 2, 5
- Family history of early-onset osteoporosis 2, 5
- Blue sclerae, dentinogenesis imperfecta, or other skeletal dysplasia features 2, 5
- Unexplained severe osteoporosis without clear secondary cause 2, 5
Gene panels for osteogenesis imperfecta, hypophosphatasia, and other monogenic bone disorders are increasingly available. 2, 5
Vertebral Fracture Assessment: The Often-Missed Component
Vertebral compression fractures are common in pediatric osteoporosis but frequently asymptomatic—they will be missed without systematic screening. 3, 5
Lateral spine radiographs (T4-L4) should be obtained in all high-risk patients, even without back pain. 3, 5
Vertebral fracture assessment (VFA) by DXA is an alternative lower-radiation option for screening, though lateral spine X-rays provide better detail. 3
A single vertebral compression fracture is diagnostic of osteoporosis regardless of BMD. 1, 5
Common Pitfalls and How to Avoid Them
Pitfall #1: Using T-scores instead of Z-scores in pediatric patients. This applies adult diagnostic criteria inappropriately and leads to overdiagnosis. Always use Z-scores. 1, 6
Pitfall #2: Diagnosing osteoporosis based on low BMD alone without fractures. A Z-score ≤ -2.0 is "low bone density for age" but NOT osteoporosis unless there are clinically significant fractures. 1
Pitfall #3: Failing to adjust BMD for body size in short or growth-delayed children. Unadjusted BMD systematically underestimates bone health in small children. Use height-adjusted Z-scores. 1, 5
Pitfall #4: Missing asymptomatic vertebral fractures. Up to 50% of vertebral fractures in children are painless. Screen with lateral spine imaging in all high-risk patients. 3, 5
Pitfall #5: Attributing all fractures to "normal childhood activity" without considering fracture characteristics. Low-trauma fractures (fall from standing height or less) in weight-bearing bones warrant evaluation, especially if recurrent. 5
Pitfall #6: Ignoring the clinical context. A child on chronic steroids with a single femur fracture from minimal trauma likely has osteoporosis even if Z-score is -1.5. Clinical judgment matters. 5
Pitfall #7: Comparing serial DXAs from different machines or facilities. Precision errors make cross-machine comparisons unreliable. Use the same DXA system for follow-up. 1