Decreased Vitamin D

Subnormal serum 25-hydroxyvitamin D concentration predisposing to osteomalacia in adults, rickets in children, and reduced bone mineralization.

• Deficient: <12 ng/mL or <30 nmol/L

• Insufficient: 12–20 ng/mL or 30–50 nmol/L

Causes

• Limited sun exposure

• Decreased dietary intake

  • Dairy products

  • Fish

  • Egg yolks

• Gastrointestinal disorders causing malabsorption

  • Celiac disease

  • Crohn's disease

  • Cystic fibrosis

• Bariatric surgery

• Impaired conversion to active vitamin D

  • Kidney failure

  • Liver failure

• Aging with reduced vitamin D synthesis

• Medications

  • Anti-seizure drugs

  • Glucocorticoids

• Obesity