Risk of fractures in vitiligo patients treated with phototherapy-A retrospective population-based cohort study

Background: Phototherapy might increase bone mineral density. However, it is unknown whether phototherapy can reduce the risk of fractures in patients with vitiligo. Objectives: To investigate the effect of phototherapy on fracture risks in vitiligo patients aged 40 or older. Methods: This population-based cohort study used the 2000-2010 Taiwan National Health Insurance Research Database (NHIRD) to identify 3863 patients newly diagnosed with vitiligo between 2003 and 2009 at age ≥40 years. Study subjects were classified into three cohorts: (1) frequent phototherapy; (2) infrequent phototherapy; and (3) no phototherapy. Patients were followed until the first hip or vertebral fracture or 31 December 2010. Data were analysed using Cox regression models and also stratified by age and gender. Results: Frequent phototherapy decreased the fracture risks (adjusted hazard ratio (aHR) = 0.32, p = 0.009) in vitiligo patients. Stratification by age and gender confirmed the fracture prevention effect of frequent phototherapy in patients aged 40-64 years (aHR = 0.14, p = 0.016) and in female patients (aHR = 0.31, p = 0.024). Conclusions: This study provides the first evidence that frequent phototherapy can reduce the risk of fractures among middle-aged and among female vitiligo patients.