Serum 25-hydroxyvitamin D and parathyroid hormone in patients with ankylosing spondylitis before and after a three-week rehabilitation treatment at high altitude during winter and spring

Does a sojourn at high altitude during the winter and spring improve vitami n D status (and possibly suppress parathyroid hormone [PTH]) in patients wi th ankylosing spondylitis (AS)? In 73 patients with AS, serum concentrations of 25-hydroxy-vitamin D [25(OH )D] and PTH were determined before and after a three-week rehabilitation tr eatment at Bad Gastein (1000 m above sea level). At the first examination, serum 25(OH)D was median (25(th), 75(th) percenti le) 15.5 ng mL(-1) (10.0 ng mL(-1), 20.6 ng mL(-1)). Thirteen patients (18% ) had a 25(OH)D concentration below 8 ng mL(-1). in 53 patients (73 %) the level was below 20 ng mL(-1). After the sojourn, 25(OH)D significantly (p = 0.02) increased to 19.7 (11.3, 24.6) ng mL(-1). PTH did not change signifi cantly, being 32 (22.4, 43.9) pg mL(-1) before and 30.3 (24.1, 39.9) pg mL( -1) after the sojourn. Analysing different periods of sojourn, a significan t (p < 0.001) increase in 25(OH)D was found in April but not in the other m onths. Patients with ankylosing spondylitis may have extremely low levels of 25(OH )D. The results of the present study suggest that a sojourn at high altitud e in early spring is liable to reduce vitamin D deficiency.