Vitamin D Deficiency in Childhood Cancer Survivors: Results from Southern Thailand

SIMPLE SUMMARY: Vitamin D deficiency, defined as a total 25-hydroxyvitamin D level of less than 20 ng/mL, is one of the major global health problems in children. There are few studies on vitamin D deficiency in childhood cancer survivors (CCSs), especially in tropical countries. Our study enrolled a total of 206 CCSs between January 2021 and March 2022 to evaluate the prevalence and risk factors for vitamin D deficiency. We found that CCSs had a high prevalence of vitamin D deficiency (35.9%), even in tropical areas such as southern Thailand. Female gender, obesity, lack of outdoor activities, and lower dietary dairy intake were independent risk factors for vitamin D deficiency. We believe that our results will be of benefit to clinicians who take care of CCSs. Regular screening should be established in long-term CCS care to identify those who are at risk of vitamin D deficiency and should be receiving appropriate supplementation. ABSTRACT: There is limited information on vitamin D deficiency among childhood cancer survivors (CSS), especially in tropical countries. The aims of this study are to determine the prevalence and risk factors for vitamin D deficiency in CCSs. This study was conducted at the long-term follow-up clinic for CCSs at Prince of Songkla University, Songkhla, Thailand. All CCSs who were followed up between January 2021 and March 2022 were enrolled. Demographic data, dietary dairy intake, average weekly duration of outdoor activities, total 25-hydroxyvitamin D [25(OH)D] levels, parathyroid hormone levels, and blood chemistry were collected. A total of 206 CCSs with a mean age at follow-up of 10.8 ± 4.7 years were included. The prevalence of vitamin D deficiency was 35.9%. Female gender (odds ratio (OR): 2.11, 95% CI: 1.08–4.13), obesity (OR: 2.01, 95% CI: 1.00–4.04), lack of outdoor activities (OR: 4.14, 95% CI: 2.08–8.21), and lower dietary dairy intake (OR: 0.59, 95% CI: 0.44–0.80) were independent risk factors for vitamin D deficiency. Vitamin D deficiency was common in CCSs and associated with female gender, obesity, lack of outdoor activities, and lower dietary dairy intake. Regular 25(OH)D screening should be established in long-term care to identify those who require vitamin D supplements.