Table 1

Mean (SD) values for summer and winter measurements

WinterSummerp Value
Vitamin D (nmol/l)35.1 (10.5)49.3 (13.0)0.000
PTH (μg/l)5.4 (1.7)4.7 (1.6)0.018
Calcium (mmol/l)2.4 (0.1)2.4 (0.1)0.239
Corrected calcium (mmol/l)2.4 (0.1)2.4 (0.1)0.375
FEV1 (l)1.18 (0.41)1.23 (0.43)0.121
FVC (l)2.66 (0.66)2.73 (0.72)0.420
PEF (l/min)205 (82)214 (87)0.650
  • There was a significant seasonal difference for vitamin D and parathyroid hormone.

  • FEV1, forced expiratory volume in 1 s; FVC, forced vital capacity; PEF, peak expiratory flow; PTH, parathormone.