Purpose: The aim of this descriptive study was to assess the prevalence of vitamin D deficiency in patients on active therapy for multiple myeloma in a tropical climate. We also tested for the association of vitamin D status on clinical outcomes.
Methods: This was a single centre, observational study performed in Townsville, Australia, which has a sunlight heavy, tropical climate. Patients on active therapy for multiple myeloma underwent testing of serum 25-hydroxyvitamin D (25(OH)D). Information on disease stage, skeletal morbidity and symptoms of peripheral neuropathy were collected from medical records and self-reported patient questionnaires.
Results: A total of 41 patients were included. With a median disease duration of 38 months, 27% were found to be vitamin D deficient. Patients with vitamin D deficiency had a higher likelihood of peripheral neuropathy compared with their non-vitamin D counterparts (73% vs. 33%, P = 0.03). Although those with vitamin D deficiency had more skeletal morbidity, this was not statistically significant (73% vs 50%, P = 0.19). Reduced 25(OH) D was associated with a poor performance status (P = 0.003). There was no association between vitamin D status and stage of myeloma.
Conclusion: There is a relatively high prevalence of vitamin D deficiency in patients with myeloma in our study. This is despite a sunlight heavy, tropical climate. We report an association between vitamin D deficiency and peripheral neuropathy. Prospective interventional trials are required to further assess this.
Keywords: Australia; Multiple myeloma; Peripheral neuropathy; Skeletal morbidity; Vitamin D.