Seasonal changes in vitamin D status and bone turnover in healthy Irish postmenopausal women

T.R. Hill, D. McCarthy, Jette Jakobsen, C. Lamberg-Allardt, M. Kiely, K.D. Cashman

Research output: Contribution to journalJournal articleResearchpeer-review


Objectives: To examine the effect of season on biochemical markers of bone turnover in 51-to 75-year-old Irish women and to investigate whether such changes are related to vitamin D status. Design: Longitudinal observational study. Setting: Cork, Ireland (52 degrees N). Subjects: 76 apparently healthy, free-living postmenopausal women (aged 51-75 years), not taking any medication and free from any condition likely to affect vitamin D status or calcium/bone metabolism. Results: Serum 25-hydroxyvitamin D [S-25(OH)D] showed a clear seasonal variation with significantly higher (p <0.001) values during late summer than late winter. Both urinary pyridinoline (Ur-Pyr) (p <0.01) and deoxypyridinoline (Ur-Dpyr) (p <0.001), but not serum parathyroid hormone or osteocalcin, showed a marked seasonal variation with lowest values during late-summer. Stratifying women into those with S-25(OH)D levels >= or <50 nmol/L (vitamin D adequate and inadequate, respectively) during late-winter, showed that Ur-Pyr and Ur-Dpyr in both groups were significantly (p <0.05) lower during late summer, and the magnitude of the reduction from winter to summer was similar in both groups. Conclusion: Seasonal changes in bone resorption markers appeared to be linked to seasonal changes in vitamin D status. Further research is needed to investigate the impact of these changes on risk of bone loss and fracture.
Original languageEnglish
JournalInternational Journal for Vitamin and Nutrition Research
Issue number5
Pages (from-to)320-325
Publication statusPublished - 2007


  • seasonal changes
  • bone turnover
  • vitamin D status


Dive into the research topics of 'Seasonal changes in vitamin D status and bone turnover in healthy Irish postmenopausal women'. Together they form a unique fingerprint.

Cite this