Risk of fractures in vitiligo patients treated with phototherapy – a retrospective population-based cohort

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 risk 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 3,863 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 risk in patients aged 40–64 years (adjusted hazard ratio=0.18, p=0.009); however, stratification by gender confirmed the fracture prevention effect of frequent phototherapy in female patients only (adjusted hazard ratio=0.19, p=0.014). Limitations: Some potential confounding variables for fractures were not available in the Taiwan NHIRD. Conclusions: This study provides the first evidence that frequent phototherapy can reduce the risk of fractures among middle-aged women with vitiligo.