5-Hydroxyvitamin D concentration in paediatric cancer patients from Scotland:a prospective cohort study

Children with cancer are potentially at high risk of plasma 25-hydroxyvitamin D [25(OH)D] inadequacy and despite UK vitamin D supplementation guidelines their implementation remains inconsistent. Thus, we aimed to investigate 25(OH)D concentration and factors contributing to 25(OH)D inadequacy in paediatric cancer patients. A prospective cohort study of Scottish children aged <18 years, diagnosed with and treated for cancer (patients) between Aug 2010-Jan 2014 was performed, with control data from Scottish healthy children (controls). Clinical and nutritional data were collected at defined periods up to 24 months. 25(OH)D status was defined by the Royal College of Paediatrics and Child Health (2013); inadequacy [<50 nmol/L: deficiency (<25 nmol/L), insufficiency (25-50 nmol/L)], sufficiency (51-75 nmol/L), optimal (>75 nmol/L). Eighty-two patients [median(IQR) age 3.9(1.9-8.8); 56% males)] and 35 controls [median(IQR) age (6.2(4.8-9.1); 49% males] were recruited. 25(OH)D inadequacy was highly prevalent in the controls (63%; 22/35), and in the patients (64%; 42/65) at both baseline and during treatment (33-50%). Non-supplemented children had the highest prevalence of 25(OH)D inadequacy at every stage with 25(OH)D median(IQR) ranging from 32.0 (21.0-46.5) nmol/L to 45.0(28.0-64.5) nmol/L. Older age at baseline [R=-0.46; p<0.001], overnutrition (BMI ≥85th centile) at 3 months [p=0.005; RR=3.1] and not being supplemented at 6 months (p=0.04; RR=4.3) may have contributed to lower plasma 25(OH)D. Paediatric cancer patients are not at higher risk of 25(OH)D inadequacy than healthy children at diagnosis; however prevalence of 25(OH)D inadequacy is still high and non-supplemented children have a higher risk. Appropriate monitoring and therapeutic supplementation should be implemented