Published: 18 Jun 2025

ICD9: 268.9      ICD10: E55.9      ICD11: 5B57

Vitamin D deficiency occurs when your body doesn't have enough vitamin D.
This essential nutrient plays a crucial role in several bodily functions, including:

Bone health: Vitamin D helps your body absorb calcium, which is vital for building and maintaining strong bones.
Immune function: Vitamin D supports a healthy immune system, helping you fight off infections and illnesses.
Cell growth: Vitamin D is involved in cell growth and differentiation.
Muscle function: Vitamin D contributes to muscle strength and function.

Causes of Vitamin D Deficiency:

Several factors can contribute to vitamin D deficiency:

Limited sun exposure: Your skin produces vitamin D when exposed to sunlight. Spending a lot of time indoors, living in areas with limited sunlight (especially during winter), wearing sunscreen, and having darker skin pigmentation can reduce vitamin D production.
Dietary factors: Few foods naturally contain significant amounts of vitamin D. Fatty fish (like salmon and tuna), egg yolks, and fortified foods (like milk, cereal, and orange juice) are sources of vitamin D. However, these may not provide enough vitamin D to meet your needs.
Malabsorption: Certain medical conditions, such as Crohn's disease, celiac disease, and cystic fibrosis, can interfere with the absorption of vitamin D from food.
Obesity: Vitamin D is fat-soluble, meaning it's stored in body fat. Obese individuals may have lower circulating levels of vitamin D because it's trapped in their fat tissue.
Kidney and liver disease: These organs play a role in converting vitamin D into its active form. Problems with these organs can lead to vitamin D deficiency.
Certain medications: Some medications, such as glucocorticoids and certain anti-seizure drugs, can interfere with vitamin D metabolism.

Symptoms of Vitamin D Deficiency:

Many people with vitamin D deficiency have no noticeable symptoms. However, when symptoms do occur, they can be vague and easily attributed to other conditions. Some potential symptoms include:

Fatigue and tiredness
Bone pain
Muscle weakness, aches, or cramps
Joint pain
Mood changes, such as depression or anxiety
Impaired wound healing
Frequent infections
Hair loss

Diagnosis and Treatment:

Vitamin D deficiency is diagnosed through a blood test that measures the level of 25-hydroxyvitamin D (25(OH)D), the main form of vitamin D in the blood.

Treatment typically involves:

Vitamin D supplements: Your doctor may prescribe vitamin D supplements, usually vitamin D3 (cholecalciferol), in varying dosages depending on your deficiency level.
Increased sun exposure: Spending more time outdoors in sunlight can help increase vitamin D production. However, it's important to practice sun safety by limiting exposure during peak hours and wearing sunscreen when necessary.
Dietary changes: Eating more vitamin D-rich foods or fortified foods can help increase your vitamin D intake.

Risk Factors:

Certain groups of people are at higher risk of vitamin D deficiency:

Older adults: As people age, their skin produces less vitamin D in response to sunlight, and their kidneys may not convert vitamin D to its active form as efficiently.
Infants and young children: Breast milk may not provide enough vitamin D for infants.
People with dark skin: Melanin, the pigment in dark skin, reduces the skin's ability to produce vitamin D in response to sunlight.
People with limited sun exposure: Those who are homebound, work indoors, or cover their skin for cultural or religious reasons are at higher risk.
People with certain medical conditions: Conditions that affect nutrient absorption or kidney/liver function can increase the risk.
Obese individuals: Vitamin D is stored in fat tissue, making it less available for use by the body.

Complications of Vitamin D Deficiency:

Severe or prolonged vitamin D deficiency can lead to serious health problems, including:

Rickets (in children): A condition that causes weak and soft bones.
Osteomalacia (in adults): A condition that causes bone pain, muscle weakness, and increased risk of fractures.
Osteoporosis: A condition that weakens bones and increases the risk of fractures.
Increased risk of falls and fractures
Potential increased risk of certain cancers, autoimmune diseases, and cardiovascular disease (although more research is needed to confirm these associations)

Prevention:

You can help prevent vitamin D deficiency by:

Getting regular sun exposure: Aim for 10-30 minutes of midday sunlight several times a week, without sunscreen (depending on your skin type and latitude).
Eating vitamin D-rich foods: Include fatty fish, egg yolks, and fortified foods in your diet.
Taking vitamin D supplements: Talk to your doctor about whether you need to take a vitamin D supplement, especially if you have risk factors for deficiency.

Important Considerations:

It is important to consult with a healthcare professional to determine if you have a vitamin D deficiency and to discuss the appropriate treatment or prevention strategies for you.
Do not self-treat with high doses of vitamin D supplements, as this can lead to vitamin D toxicity.
Sunscreen is essential to protect your skin from sun damage. It is still possible to produce some vitamin D while wearing sunscreen, although less efficiently.

This information is for general knowledge purposes only and does not constitute medical advice. Always consult with a qualified healthcare professional for any health concerns or before making any decisions related to your health or treatment.