Association among cardiorespiratory fitness, body fat, and bone marker measurements in healthy young females.
BACKGROUND
Serum vitamin D (25-hydroxyvitamin D [25(OH)D]) is important for maintaining bone health, as well as for influencing a multitude of nonosseous effects. Associations between 25(OH)D and other bone marker measurements have not been well studied in relation to obesity and cardiorespiratory fitness in healthy young females.


OBJECTIVE
To determine if there is an association of cardiorespiratory fitness and body fat with bone marker measurements (ie, 25[OH]D and calcium) in healthy young females at peak bone mass.


METHODS
Females younger than 25 years were recruited as volunteer participants. From July 2007 to October 2007, participants were assessed for cardiorespiratory fitness by measuring maximal oxygen consumption (VO(2) max). In addition, their levels of serum 25(OH)D and serum total calcium were analyzed. Finally, percent body fat was measured using dual-energy x-ray absorptiometry of the whole body. Pearson correlation coefficients were used to evaluate the association of fitness and body fat with bone marker measurements.


RESULTS
A total of 59 adolescent girls and young women-were recruited. A statistically significant, positive association was found between VO(2) max and serum 25(OH)D levels (Pearson r=0.36; P<.05), but not between VO(2) max and serum total calcium levels (Pearson r= -0.10, P>.05). Percent body fat was inversely associated with both VO(2) max (Pearson r= -0.70, P<.05) and 25(OH)D levels (Pearson r= -0.44, P<.05).


CONCLUSIONS
In healthy young females, better cardiorespiratory fitness, as measured by VO(2) max level, and lower percent body fat are associated with higher serum 25(OH)D level. This response is independent of serum total calcium level.
Department of Biology, Bruner Hall of Science, Kearney, NE 68849-0001, USA. mowryda1@unk.edu
Debra A
DA
Mowry
Megan M
MM
Costello
Kate A
KA
Heelan
D000273:Adipose Tissue; D000293:Adolescent; D000367:Age Factors; D015415:Biomarkers / Q000097:blood; D015519:Bone Density; D002118:Calcium / Q000097:blood; D002320:Cardiovascular Physiological Phenomena; D017079:Exercise Tolerance; D005260:Female; D006801:Humans; D016014:Linear Models; D010101:Oxygen Consumption; D010809:Physical Fitness; D012143:Respiratory Physiological Phenomena; D012306:Risk; D012307:Risk Factors; D011795:Surveys and Questionnaires; D014807:Vitamin D / Q000031:analogs & derivatives / Q000097:blood; D016387:Women's Health; D055815:Young Adult
D015415:Biomarkers; D014807:Vitamin D; C104450:25-hydroxyvitamin D; D002118:Calcium