What are the manifestations and treatment options for vitamin D deficiency?

Vitamin D Deficiency: Manifestations and Treatment

Vitamin D deficiency presents with a range of clinical manifestations including bone pain, muscle weakness, increased risk of fractures, and falls, and should be treated with appropriate vitamin D supplementation based on severity of deficiency.

Clinical Manifestations

Musculoskeletal Manifestations

• Symmetric low back pain 1
• Proximal muscle weakness 1, 2
• Muscle aches 1
• Throbbing bone pain elicited with pressure over the sternum or tibia 1
• Increased risk of falls due to muscle weakness 3
• Osteopenia and osteoporosis 3
• Osteomalacia (in severe deficiency) causing aching bone pain that is often misdiagnosed as fibromyalgia or chronic pain syndrome 3

Extra-skeletal Manifestations

• Increased risk for cardiovascular disease 4, 5
• Potential increased risk for type 1 and type 2 diabetes mellitus 4, 5
• Possible increased risk for certain cancers, especially colon and prostate 4, 5
• Potential association with depression 6
• Functional limitations 6

Risk Factors for Vitamin D Deficiency

• Low vitamin D intake 6
• Decreased vitamin D absorption 6
• Limited sun exposure due to:
  • Winter season 6
  • High latitude 6
  • Physical sun avoidance 6
  • Sunscreen use 3
• Obesity (may allow greater sequestration of vitamin D into adipose tissue) 6
• Darker skin pigmentation (reduces skin's ability to produce vitamin D in response to UVB exposure) 6
• Older age 6
• Female sex 6

Diagnosis

• Serum 25-hydroxyvitamin D [25(OH)D] is the best measure of vitamin D status 3
• Vitamin D deficiency is defined as serum 25(OH)D level of less than 20 ng/mL (50 nmol/L) 1
• Vitamin D insufficiency is defined as serum 25(OH)D level of 20 to 30 ng/mL (50 to 75 nmol/L) 1
• Optimal serum 25(OH)D level should be approximately 30 ng/mL or above 4

Treatment Recommendations

For Vitamin D Deficiency

• Oral ergocalciferol (vitamin D2) at 50,000 IU per week for eight weeks 1
• After normalization of vitamin D levels, maintenance with cholecalciferol (vitamin D3) at 800-1,000 IU per day from dietary and supplemental sources 1

For Prevention

• Daily dietary vitamin D intake of 600 IU in adults aged 18 to 70 years 6
• Daily dietary vitamin D intake of 800 IU in adults older than 70 years 6
• For patients at high risk for vitamin D deficiency, supplementation with 800-1,000 IU of vitamin D3 daily is recommended 6, 3
• Calcium intake of 1,000-1,500 mg daily is recommended alongside vitamin D supplementation 6

Special Considerations

• For patients with inflammatory bowel disease receiving corticosteroids, supplementation with 800-1,000 IU/day vitamin D and 800-1,000 mg/day calcium is recommended 6
• For HIV-infected individuals, 800-1,000 IU of vitamin D daily along with 1,000-1,500 mg of calcium is recommended due to high prevalence of low BMD 6
• In patients with chronic kidney disease, vitamin D levels should be measured once per year 6

Potential Harms of Treatment

• Vitamin D toxicity is rare but can occur with excessive supplementation 6
• Toxicity is associated with 25(OH)D levels above 200 ng/mL (500 nmol/L) 6
• Symptoms of toxicity include:
  • Hypercalcemia with anorexia, nausea, weakness, weight loss, vague aches and stiffness, constipation 7
  • Impairment of renal function 7
  • Widespread calcification of soft tissues 7
  • Treatment with vitamin D plus calcium may increase risk for kidney stones; vitamin D alone does not seem to increase this risk 6

Monitoring

• After initiating treatment, serum levels of calcium and phosphorus should be measured at 1 month following initiation or change in dose of vitamin D 6
• Once vitamin D levels normalize, yearly monitoring of 25(OH)D levels is recommended 6

Important Considerations

• Vitamin D deficiency is pandemic, affecting approximately three-quarters of all adults when using the optimal level definition of 30 ng/mL 4
• African Americans have paradoxically lower reported rates of fractures despite having increased prevalence of low vitamin D levels compared to white persons 6
• Increased sun exposure is generally not recommended as treatment of vitamin D deficiency due to increased risk for skin cancer 6
• Vitamin D supplementation of at least 700-800 IU per day has been shown to reduce fracture and fall rates in adults 1