Lunar Accelerated Bone Loss
Earth designation: Osteoporosis
Accelerated reduction in bone mineral density caused by reduced gravitational loading. On Earth, osteoporosis develops over decades; in lunar gravity, residents can lose 1-2% bone density per month in weight-bearing bones without countermeasures. Long-term residents risk spontaneous fractures from activities that would be routine on Earth.
Lunar Risk Factors
Reduced gravitational loading is the primary driver — bones adapt to the lower force requirements. Vitamin D synthesis is impaired (no UV exposure in habitats). Calcium metabolism alterations. Physical inactivity. Limited dietary calcium if hydroponics supply is disrupted.
Symptoms
Often asymptomatic until fracture. Back pain from vertebral compression. Height loss. Fragility fractures from minor trauma.
Lunar Presentation
Regular DXA scanning reveals bone loss before symptoms. First symptomatic fractures often occur during physical work in mining, construction, or even vigorous exercise.
Diagnosis
DXA (dual-energy X-ray absorptiometry) — portable units available in medical bay. FRAX score adapted for lunar context. Serum calcium, phosphate, vitamin D, PTH.
Treatment
Bisphosphonates, resistance exercise, calcium and vitamin D supplementation.
Lunar Medical Bay Protocol
Mandatory resistance exercise protocol (minimum 90 min/day). Bisphosphonate therapy (zoledronic acid annually or weekly alendronate) for residents with >3% loss in any 6-month period. Vitamin D supplementation 2000-4000 IU daily. Calcium 1500 mg/day. Protein intake optimization. Quarterly DXA monitoring. Earth telemedicine endocrinology if not responding to first-line therapy.
Evacuation Criteria
Vertebral compression fracture causing neurological compromise. Bone density T-score <-3.5 with ongoing loss despite maximum therapy. Hip fracture (consider surgical repair capacity before evacuation).
Prevention
Mandatory exercise protocol before lunar deployment. Baseline DXA. Resistance exercise with loaded suits. Bisphosphonate prophylaxis for missions >12 months. Nutrition protocol enforcement.