Symptoms of Vitamin D Deficiency
The primary symptoms of vitamin D deficiency include symmetric low back pain, proximal muscle weakness, muscle aches, throbbing bone pain (especially when pressure is applied over the sternum or tibia), fatigue, and unexplained anemia. 1, 2
Common Clinical Manifestations
Vitamin D deficiency can present with various symptoms affecting multiple body systems:
Musculoskeletal Symptoms
- Symmetric low back pain
- Proximal muscle weakness (difficulty standing from a squatting position)
- Muscle aches and generalized pain
- Throbbing bone pain elicited with pressure over the sternum or tibia
- Increased risk of falls, especially in older adults 1, 2
Other Common Symptoms
Severe Deficiency Manifestations
When vitamin D deficiency becomes severe, more serious conditions can develop:
- In children: Rickets (bone mineralization disease)
- In adults: Osteomalacia (softening of the bones)
- Secondary hyperparathyroidism
- Increased fracture risk due to reduced bone mineral density
- Reduced efficacy of anti-fracture medications 1
Risk Factors for Vitamin D Deficiency
Identifying patients at risk is important for early detection:
- Limited UVB exposure (minimal sun exposure)
- Inadequate dietary vitamin D intake
- Darker skin pigmentation
- Advanced age (especially those >70 years)
- Obesity
- Malabsorption conditions
- Severe liver or kidney disease
- Institutionalized individuals 1
Diagnostic Considerations
Vitamin D status is determined by measuring serum 25-hydroxyvitamin D (25-OHD) levels:
- Deficiency: <20 ng/mL (50 nmol/L)
- Insufficiency: 20-30 ng/mL (50-75 nmol/L)
- Optimal levels: 30-40 ng/mL or higher 1, 2
Clinical Pitfalls and Caveats
Symptom overlap: Many vitamin D deficiency symptoms (fatigue, muscle pain) can mimic other conditions, leading to missed diagnoses.
Silent deficiency: Some patients may have laboratory evidence of deficiency without obvious symptoms but remain at increased risk for long-term complications.
Seasonal variation: Vitamin D levels typically decrease during winter months in temperate climates, which may exacerbate symptoms.
Response to treatment: Improvement in symptoms with vitamin D supplementation is an important diagnostic clue - approximately 85% of patients regain the ability to stand from a squatting position after 2-6 months of treatment 1.
Beyond bone health: While musculoskeletal symptoms are most recognized, vitamin D deficiency is also associated with increased risk of cardiovascular disease, autoimmune disorders, certain cancers, and increased all-cause mortality 1, 4.
Remember that maintaining adequate vitamin D levels is crucial not only for symptom relief but also for reducing the risk of fractures, falls, and other adverse health outcomes associated with vitamin D deficiency.