Symptoms of Low Vitamin D
Vitamin D deficiency most commonly presents with bone and muscle pain, muscle weakness, fatigue, and in severe cases, skeletal deformities (rickets in children, osteomalacia in adults). 1
Musculoskeletal Symptoms
The hallmark manifestations of vitamin D deficiency involve the musculoskeletal system:
- Bone pain: Isolated or generalized aches and pains in bones, often described as symmetric low back pain or throbbing bone pain elicited with pressure over the sternum or tibia 1, 2
- Muscle weakness: Proximal muscle weakness is characteristic; children have difficulty standing and walking, while elderly patients experience increased postural sway and more frequent falls 1, 2
- Muscle cramps and aches: These symptoms correlate significantly with lower vitamin D levels 3
Skeletal Manifestations
The mineralization defects caused by vitamin D deficiency lead to:
- Rickets in children: Skeletal deformities occur because children have minimal skeletal mineral reserves 1
- Osteomalacia in adults: This mineralization defect often goes undetected because closed epiphyseal plates prevent obvious deformities, but it decreases bone mineral density and causes generalized discomfort 1
Non-Specific Symptoms
Research has identified additional symptoms associated with low vitamin D levels, though the evidence is less robust:
- Fatigue: Patients with vitamin D deficiency more frequently report tiredness compared to those with normal levels 3, 4
- Mood changes: Mood swings and depression have been linked to hypovitaminosis D 3, 5
- Hair loss: Correlates with lower vitamin D levels 3
- Weight gain: Associated with vitamin D deficiency 3
Important Clinical Context
Many patients with vitamin D deficiency remain asymptomatic or have only subtle symptoms. A mild deficiency may cause only tiredness and general aches, while more severe deficiency produces the classic skeletal manifestations 5. The 2011 Endocrine Society guideline emphasizes that osteomalacia often goes undetected in adults because symptoms can be vague 1.
Pathophysiology of Symptoms
The symptoms arise from secondary hyperparathyroidism triggered by vitamin D deficiency. This leads to:
- Decreased intestinal calcium and phosphorus absorption
- Elevated PTH mobilizing calcium from bone
- Phosphorus wasting in kidneys
- Inadequate calcium-phosphorus product causing mineralization defects 1
Clinical Pitfall
Do not rely solely on symptoms to diagnose vitamin D deficiency. The 2024 Endocrine Society guideline notes that routine screening based on symptoms alone is not recommended for the general population 6. However, measuring 25(OH)D is reasonable in high-risk groups (those with malabsorption, obesity, dark skin, limited sun exposure, elderly, pregnant women) who present with these symptoms 1.