Comparative levels of 25hydroxyvitamin D (25OHD), parathyroid hormone (PTH) and bone remodelling markers at the end of winter vs. the end of summer in pre- and postmenopausal women living in the south of Argentina.

GONZALES CHAVES M; PONCE G; FAJARDO MA; PELLEGRINI G; FRIEDMAN SM; SOMOZA J; ZENI SN

Viena , Austria

Conferencia; International Conference on Progress in bone and mineral research; 2006

Asociación Austriaca de Osteología y MEtabolismo Mineral

Young adults may be at risk of having inadequate vitamin D status. Levels of 25HOD were evaluated at the end of winter and summer to observe whether changes in vitamin D status have an effect on PTH and bone markers. Healthy women (45°S) (10 pre and 10 postmenopausal) were studied in March and August, respectively. In fasting blood 25HOD (ELISA, Diasorin), PTHmm (RIA), bone alkaline phosphatase (b-ALP), collagen type I N-terminal propeptide  (P1NP), b-CTX (EQL, Elecsys) and in urine CTX (ug/mmol creatinine) (Crosslaps, Osteometer Bio Tech) were evaluated. Mean±SD are the following:                                                       Premenopausal                                   Postmenopausal          Winter     Summer     Winter    Summer 25HOD (ng/ml) 14.7±5.6 26.5±10.6* 12.4±4.0 25.4±10.0* PTHmm (pg/ml) 46.0±9.0 26.5±7.0* 46.3±10.6 35.2±15.0 b-ALP (IU/L) 56±11 63±10 63±17 78±17# P1NP (ng/ml) 55.0±12.1 46.2±10.6 59.4±16.6 63.6±20.7# b-CTX (ng/L) 210.2±49.9 213.2±89.5 213.2±89.5 356.6±156.5#       CTXu (ug/mmolCreatinine) 188.9±65.6 146.1±48.7 234.9±110.7 232.4±98.5#    (*) p<0.05: summer vs winter within the same group, (#) p<0.05: pre vs. postmenopausal in the same season. Both groups had vitamin D insufficiency in winter and only premenopausal women presented a significant increment in PTH, without an increase in bone markers. Although 25OHD increased approximately 95% in summer, their vitamin D status was still deficient. Only bone markers were significantly different between pre-and postmenopausal summer values. Conclusion: vitamin D insufficiency in winter was still deficient in summer. Grant from Bs Aires University M033.