Vitamin D status,dietary intake,and bone turnover in female Soldiers during military training: A longitudinal study

Background: vitamin d is an essential nutrient for maintaining bone health,to include protecting against stress fracture during periods of rapid bone turnover. the objective of this longitudinal,observational study was to assess vitamin d status,biomarkers of bone turnover,and vitamin d and calcium intake in female soldiers (n = 91) during us army basic combat training (bct).methods: anthropometric,biological and dietary intake data were collected at wk 0,3,6,and 9 of the 10 wk bct course. mixed models repeated measures anovas were used to assess main effects of time,race,and time-by-race interactions.results: white volunteers experienced a decrease in serum 25(oh)d levels,whereas non-white volunteers experienced an increase during bct. however,serum 25(oh)d levels were lower in non-whites than whites at all timepoints (p-interaction < 0.05). group mean pth levels increased (p < 0.05) during the first 3 wk of training,remained elevated for the duration of bct,and were higher in non-whites compared to whites (p-race < 0.05). biomarkers of both bone formation (bone alkaline phosphatase and procollagen i n-terminal peptide) and resorption (tartrate-resistant acid phosphatase and c-terminal telopeptide) increased (p < 0.05) during bct,indicating increased bone turnover. estimated daily intakes of vitamin d and calcium were below recommended levels (15 μg and 1000 mg/day,respectively),both before (group mean ± sem; 3.9 μg/d ± 0.4 and 887 mg/d ± 67) and during bct (4.1 μg/d ± 0.3 and 882 mg/d ± 51).conclusions: these findings demonstrate that female soldiers experience dynamic changes in vitamin d status coupled with increased bone turnover and potentially inadequate vitamin d and calcium intake during military training. © 2012 lutz et al.; licensee biomed central ltd.