Vitamin D Deficiency More Prevalent in Childhood Cancer Survivors

Today, nearly 80% of children diagnosed with cancer survive, which is defined as living cancer-free for at least 5 years after diagnosis. However, the long-term complications of physical inactivity, chronic inflammation, nutritional challenges, and exposure to corticosteroids, antineoplastic agents, and radiation can persist.

The National Cancer Institute’s Childhood Cancer Survivor Study documented many long-term health problems, including second primary cancers, reproductive complications, psychosocial issues, and fractures. Recently, a large study that appeared online ahead of print in Clinical Endocrinology indicated that survivors of childhood cancers have increased risk for vitamin D anomalies.

Because survivors’ bone health may already be compromised by their previous cancer and its treatment, low vitamin D concentrations probably have more clinical significance in these patients than others. Vitamin D deficiency may further increase the risk of immune dysfunction, diabetes, and malignancy.

The study enrolled a previously examined group of 208 cancer survivors—108 of whom were pediatric patients aged 5 to 17 years, and 99 of whom were adult patients aged 18 to 39 years—and then compared their vitamin D levels to 132 pediatric and 1393 adult control subjects. Looking for links to vitamin D changes, the researchers considered a number of factors, including radiation, bone marrow transplantation, treatment intensity, weight, hyperinsulinism, or abnormal glucose tolerance.

Although the investigators found similar vitamin D concentrations in the pediatric survivors and controls, regardless of age or sex, adult survivors were more than twice as likely to have vitamin D deficiency (<50 nmol/L) than control subjects.

Only time since diagnosis was identified as a factor related to low vitamin D levels.

The researchers reported that adult survivors of childhood cancer are at increased risk for vitamin D anomalies compared with the general population. Therefore, clinicians are advised to maintain a high index of suspicion for vitamin D deficiency.