Vitamin D deficiency in multiple myeloma

Vitamin D has long been recognized as a fundamental mediator of calcium and skeletal homeostasis. More recently, however, the important role that vitamin D plays in a wide variety of other cellular processes, including inhibition of carcinogenesis by induction of differentiation, inhibition of cellular proliferation and angiogenesis, and promotion of apoptosis, has been appreciated. Multiple myeloma, a severely debilitating, incurable, and uniformly fatal neoplastic disease of B cell origin, is frequently complicated by severe skeletal complications related to lytic bone destruction. The role that vitamin D may play in myeloma bone disease and/or multiple myeloma itself, however, has remained unknown. Here, we review our recent study of 148 subjects who had their vitamin D status determined within 2 weeks of a new clinical diagnosis of multiple myeloma. The prevalence of vitamin D deficiency (defined as a serum 25-hydroxyvitamin D level <20 ng/mL (50 nmol/L)) increased in parallel with International Staging System categorization, indicating that subjects with worse clinical prognosis were more likely to have vitamin D deficiency. However, vitamin D levels were not predictive of skeletal morbidity. These data provide the first data demonstrating an inverse association between vitamin D status and clinical prognosis in patients with multiple myeloma. Further, these data suggest that assessment of vitamin D status may be an important adjunctive aspect of providing care for patients with myeloma, and that larger prospective studies to assess the role of vitamin D in multiple myeloma disease progression, overall survival, and quality of life may be warranted.