Updated October 21, 2026 — Written by Dr. Shabbir Hussain, BPT, Registered Physiotherapist | Clinical Rehabilitation Specialist

Quick Answer

Vitamin D deficiency in children and adolescents with sickle cell disease (SCD) has been associated with more frequent painful episodes, hospitalizations, and certain complications affecting the bones, kidneys, and lungs. A 2026 systematic review of 12 studies identified these associations, although researchers could not establish whether low vitamin D directly causes more severe disease. Testing and treating a confirmed deficiency may be appropriate under medical supervision, but vitamin D supplements are not a proven treatment for preventing sickle cell pain crises.

What Did the New Research Find?

Vitamin D deficiency was associated with vaso-occlusive crises (VOCs) in the research reviewed. VOCs were the most frequently reported clinical outcome, appearing in 25% of the studies included in the systematic review.

During a VOC, sickled red blood cells can obstruct small blood vessels, restricting blood flow and causing episodes of severe pain. Some episodes require emergency treatment or hospitalization.

However, the review does not establish that low vitamin D directly causes these crises. More research is needed to determine whether correcting a deficiency can reduce the frequency or severity of pain episodes.

Can Low Vitamin D Increase Sickle Cell Pain Crises?

Vitamin D deficiency was associated with painful vaso-occlusive crises (VOCs) in several studies included in the review.

VOCs occur when sickled red blood cells obstruct small blood vessels, restricting blood flow and oxygen delivery to tissues. These episodes can cause severe pain and may require emergency treatment or hospitalization.

Some studies found that children experiencing pain crises had lower vitamin D levels than those without such episodes. Lower levels were also associated with chronic pain in one study.

However, an association does not prove that vitamin D deficiency causes pain crises. More research is needed to determine whether correcting a deficiency can reduce their frequency.

What Other Complications Were Associated With Vitamin D Deficiency?

The review identified several additional findings:

• Hospitalizations: Some studies associated vitamin D deficiency with more frequent hospital admissions, longer hospital stays, and increased emergency visits for pain.
• Bone health: Low vitamin D levels were linked to weaker bones or more frequent fractures in some studies, although findings were inconsistent.
• Kidney health: One study identified an association between vitamin D deficiency and markers of structural kidney damage.
• Lung function: One study reported an association between lower vitamin D levels and poorer lung function, although other lung-related findings were not significant.
• Anemia and hemolysis: Some studies reported lower hemoglobin levels and higher markers of red blood cell breakdown among children with vitamin D deficiency.

These results suggest that vitamin D status deserves attention, but the evidence does not establish that deficiency causes these complications.

Why Is Vitamin D Important for Children With Sickle Cell Disease?

Vitamin D helps the body absorb calcium and maintain healthy bones. It also participates in immune regulation and other biological processes.

Children with SCD already face an increased risk of certain bone complications. Identifying and correcting vitamin D deficiency may help support their bone health and overall nutritional status.

However, the researchers noted important limitations. The studies differed in their methods and outcome measurements, and many had relatively small sample sizes. The evidence also could not establish whether low vitamin D contributes to more severe SCD or results from the effects of the disease.

Should Children With Sickle Cell Disease Take Vitamin D Supplements?

Children with SCD who have confirmed vitamin D deficiency should discuss treatment with their pediatrician or hematologist.

A healthcare professional may recommend a blood test measuring 25-hydroxyvitamin D, followed by supplementation if appropriate. The dose and duration depend on factors such as the child’s age, vitamin D level, diet, and medical history.

Families should avoid giving high-dose vitamin D supplements without medical guidance because excessive intake can cause dangerously high calcium levels and kidney problems.

Importantly, vitamin D supplementation should not replace established sickle cell treatments, prescribed medicines, pain-management plans, or recommended medical screenings.

How Physiotherapy Can Help

Physiotherapy may support children with SCD who experience reduced mobility, muscle weakness, or difficulties returning to everyday activities after a painful episode.

Depending on the child’s condition, a physiotherapist may recommend gentle mobility exercises, gradual strengthening, and individualized activity planning.

Exercise should be adapted to the child’s tolerance and medical status. Dehydration, extreme temperatures, and excessive exertion can increase the risk of sickle cell complications. During an acute pain crisis, fever, chest pain, or breathing difficulties, urgent medical assessment takes priority over exercise.

Physiotherapy cannot correct vitamin D deficiency or cure sickle cell disease, but appropriate rehabilitation may help maintain function and support recovery.

The Bottom Line

A 2026 systematic review found that vitamin D deficiency in children and adolescents with sickle cell disease was associated with pain crises, hospitalizations, and certain bone, kidney, lung, and blood-related complications.

The findings support paying attention to vitamin D status as part of comprehensive care. However, further research is needed before supplementation can be recommended specifically to prevent sickle cell pain crises or organ damage.

Families should consult their child’s healthcare team about testing and appropriate treatment rather than starting high-dose supplements independently.

MEDICAL SOURCES

1. PubMed — A systematic review on clinical and laboratory effects of vitamin D deficiency in children with sickle cell disease. The 2026 review of 12 studies. Original research on PubMed
2. SAGE Journals — A systematic review on clinical and laboratory effects of vitamin D deficiency in children with sickle cell disease. The original research publication. Nutrition and Health research paper
3. CDC — Prevention and Treatment of Sickle Cell Disease Complications. Guidance on established approaches to preventing and managing SCD complications. CDC clinical guidance
4. CDC — Vitamin D: Infant and Toddler Nutrition. Background on vitamin D’s role in children’s bone health. CDC vitamin D guidance

MEDICAL DISCLAIMER

This article is for general educational and informational purposes only. It is not a substitute for professional medical diagnosis, treatment, or individualized medical advice. If you have persistent, severe, worsening, or concerning symptoms, consult a qualified healthcare professional. Seek urgent medical care for emergency symptoms.