Understanding What Disease Is Caused by Lack of Vitamin D and Its Broader Impact

October 4, 2025 •

4 min read

According to the National Institutes of Health, vitamin D deficiency is a worldwide problem, with certain populations at higher risk, such as the elderly, obese individuals, and people with darker skin. A primary and well-known health concern is what disease is caused by lack of vitamin D, which directly affects bone mineralization and strength.

Quick Summary

Chronic or severe vitamin D deficiency causes bone disorders like rickets in children and osteomalacia in adults. A deficiency also correlates with higher risks of osteoporosis, autoimmune diseases, and chronic conditions like heart disease and diabetes.

Key Points

Rickets: The primary disease in children caused by lack of vitamin D, leading to softened bones and skeletal deformities.
Osteomalacia: The adult equivalent of rickets, causing bone softening, pain, and increased fracture risk due to defective mineralization.
Bone Density Loss: Prolonged deficiency contributes to osteoporosis, making bones brittle and fragile, particularly in older adults.
Beyond Bone Health: Low vitamin D is correlated with higher risks for autoimmune diseases, cardiovascular conditions, depression, and frequent infections.
Prevention is Key: A combination of adequate sun exposure, dietary intake from fatty fish and fortified foods, and supplements can prevent deficiency.
Diet and Supplements: Since many foods are not naturally rich in vitamin D, fortified products and supplements are often essential to meet daily requirements.

The Primary Diseases Caused by Vitamin D Deficiency

Vitamin D plays a critical role in the body's ability to absorb calcium and phosphorus, which are essential for building and maintaining healthy bones. Without enough vitamin D, the body cannot properly mineralize bone tissue, leading to several serious conditions.

Rickets: The Childhood Bone Disorder

Rickets is a condition that causes bones to soften and weaken in children. Because a child's skeleton is still growing, the failure of the growth plate to properly mineralize can lead to significant skeletal deformities. While largely eradicated in many developed countries due to fortified foods, it is seeing a resurgence in some areas and remains a public health concern globally.

Common symptoms of rickets include:

Bone pain: Aches and discomfort in the spine, pelvis, and legs.
Skeletal deformities: Bowed or bent legs, thickened ankles and wrists, and a widened rib cage known as a rachitic rosary.
Growth retardation: Incorrect growth patterns and delayed physical development.
Muscle weakness: General muscle pain and weakness.
Hypocalcemia: Low blood calcium levels, which in severe cases can cause muscle spasms or seizures.

Osteomalacia: The Adult Counterpart

Osteomalacia is the adult form of rickets, where bones soften due to a defect in bone mineralization. Unlike children, adults' bones have finished growing, so the condition primarily results in weakened bones, bone pain, and an increased risk of fractures.

Symptoms of osteomalacia often include:

Chronic, deep bone pain: Most commonly in the spine, pelvis, and legs.
Muscle weakness: Particularly in the upper arms and thighs, leading to difficulty climbing stairs or getting up from a chair.
Increased fracture risk: Bones, especially in the hips, may break with minimal trauma.
Fatigue: A general feeling of tiredness and low energy.

Comparison: Rickets vs. Osteomalacia

While both conditions stem from the same core problem of impaired bone mineralization, the key difference lies in the age of onset and its effects on the skeleton.


Feature	Rickets (Children)	Osteomalacia (Adults)
Skeletal Impact	Affects the developing growth plates and overall bone structure, causing deformities.	Affects existing, fully grown bones, causing softening and weakening.
Primary Symptoms	Bowed legs, skeletal deformities, and growth problems.	Chronic bone pain, muscle weakness, and fatigue.
Fracture Risk	Increased risk of fractures due to softened bones.	Increased risk of fractures, especially in the hips and spine.
Reversibility	Often reversible with treatment, though severe deformities may require surgery.	Reversible with treatment to improve bone strength and reduce pain.
Underlying Cause	Failure of growing cartilage to calcify into bone.	Defective mineralization of bone that is already formed.

Beyond Bone Health: Other Potential Links

While bone disorders are the most direct result of vitamin D deficiency, a growing body of research has linked low vitamin D levels to a range of other chronic health issues. It is important to note that many of these links are still under investigation, but the correlations are significant.

Osteoporosis: Chronic vitamin D deficiency contributes to bone density loss over time, which can precipitate or worsen osteoporosis, a condition characterized by porous and brittle bones.
Autoimmune Diseases: Studies have shown associations between low vitamin D levels and an increased risk of autoimmune diseases, including multiple sclerosis, type 1 diabetes, and rheumatoid arthritis.
Cardiovascular Disease: Some research suggests a link between vitamin D deficiency and higher risks of cardiovascular problems, including hypertension.
Mental Health: Low vitamin D levels have been associated with mood changes, including depression and Seasonal Affective Disorder (SAD).
Increased Infections: Vitamin D plays a role in immune function, and a deficiency can lead to a heightened risk of infection.

Causes of Vitamin D Deficiency and Prevention Strategies

A vitamin D deficiency can stem from a variety of factors, including inadequate sun exposure, dietary intake, and underlying health conditions. The body produces vitamin D naturally when the skin is exposed to sunlight's ultraviolet-B (UVB) rays, but this process can be hampered by geography, darker skin pigmentation, and sunscreen use.

To prevent vitamin D deficiency, it is important to incorporate multiple sources into your lifestyle:

Sensible Sun Exposure: Aim for 10–30 minutes of direct sunlight exposure several times per week, depending on your skin tone, location, and the time of year.
Dietary Sources: Few foods naturally contain significant vitamin D, but some excellent options include:
- Fatty fish (salmon, tuna, mackerel)
- Cod liver oil
- Egg yolks
- Some mushrooms, especially those exposed to UV light
Fortified Foods: Many common products have vitamin D added during processing, such as milk, certain cereals, orange juice, and plant-based milks.
Supplements: For many, especially those at high risk, supplements are the most reliable way to maintain adequate levels. Supplements are available in two forms: vitamin D2 (ergocalciferol) and vitamin D3 (cholecalciferol), with D3 often being cited as more effective at raising blood levels. It is crucial to consult a healthcare provider for the correct dosage to avoid toxicity.

For more detailed information on preventing vitamin D deficiency, including specific dietary and lifestyle recommendations, consult a reliable resource such as the Harvard T.H. Chan School of Public Health.

Conclusion

Vitamin D is a crucial nutrient, and its deficiency can lead to serious bone-related illnesses. Rickets, which causes bone deformities in children, and osteomalacia, resulting in soft and weakened bones in adults, are the most direct consequences. Furthermore, evidence links low vitamin D levels to a range of other chronic conditions, including osteoporosis, autoimmune disorders, and mental health issues. By combining sensible sun exposure, a balanced diet that includes vitamin D-rich and fortified foods, and supplements when necessary, individuals can effectively prevent deficiency and support overall health and well-being. Regular consultation with a healthcare provider can help determine the best prevention and treatment strategy for your specific needs.

Frequently Asked Questions

The most direct diseases caused by a lack of vitamin D are rickets in children and osteomalacia in adults. Both conditions result from inadequate mineralization of the bones.

Common symptoms can include fatigue, bone and muscle pain, muscle weakness, bone loss, and mood changes like depression. In severe cases, symptoms are more pronounced, with skeletal deformities in children and fractures in adults.

Chronic vitamin D deficiency can contribute to and exacerbate osteoporosis by causing a loss of bone density. While not the sole cause, it is a significant risk factor.

Adequate vitamin D can be obtained through sensible sun exposure, eating foods naturally containing it (like fatty fish) or fortified with it (like milk and cereals), and taking supplements.

Yes, taking excessive amounts of vitamin D supplements can lead to toxicity (hypervitaminosis D), which can cause high blood calcium levels. This can result in nausea, vomiting, weakness, and potential damage to the heart and kidneys.

Research suggests an association between low vitamin D levels and mood changes, including depression and Seasonal Affective Disorder (SAD). Some studies show that supplementation may help relieve symptoms.

Rickets affects growing children, causing soft bones and deformities because the growth plates don't mineralize properly. Osteomalacia affects adults, causing existing bones to soften and weaken after growth is complete.