Theorell-Haglöw J, et al. - This randomized sham-controlled trial aimed to examine whether continuous positive airway pressure treatment could modulate serum vitamin D (25-hydroxyvitamin D) and bone turnover markers (collagen-type 1 cross-linked C-telopeptide, osteocalcin and N-terminal propeptide of type 1 collagen). The researchers demonstrated that compared with sham, 12 weeks of continuous positive airway pressure did not modulate vitamin D or modulate any of the bone turnover markers. It was, however, plausible that in selected groups of patients with obstructive sleep apnea, continuous positive airway pressure could have late beneficial effects on vitamin D levels and bone turnover markers.