Retinol, retinol-binding protein 4, abdominal fat mass, peak bone mineral density, and markers of bone metabolism in men: the Northern Osteoporosis and Obesity (NO2) Study.
BACKGROUND
The association between retinol and bone mineral density (BMD) in males after puberty has not been fully investigated previously.


OBJECTIVE
To investigate the association between retinol, retinol-binding protein-4 (RBP-4), BMD (g/cm(2)), abdominal fat mass, and markers of bone metabolism in young men.


METHODS
Longitudinal study.


METHODS
Seventy-eight healthy males with a mean age of 22.6+/-0.7 years at baseline. A follow-up was conducted in 73 of the participants 2.0+/-0.4 years later.


METHODS
Associations between serum concentrations of retinol and RBP-4, and BMD of the total body, lumbar spine, and hip, serum concentrations of osteocalcin, and carboxy terminal telopeptide of type 1 collagen (CTX), were investigated.


RESULTS
Both retinol and RBP-4 showed an inverse relationship with that of osteocalcin (r=-0.23 to -0.25, P<0.05). Levels of RBP-4 (r=0.26, P=0.02) and osteocalcin (r=-0.23, P=0.04) were also related to abdominal fat mass, and the relationship between RBP-4, retinol, and osteocalcin disappeared after adjusting for this influence of abdominal fat mass. Neither retinol nor RBP-4 concentrations were associated with BMD at any site, CTX as baseline, or changes in BMD during the 2-year follow-up period. Levels of RBP-4 showed a strong association with levels of retinol (r=0.61, P<0.001).


CONCLUSIONS
We found a negative association between the bone formation marker osteocalcin with retinol and RBP-4. The association disappeared when adjusting for the influence of abdominal fat mass. Neither retinol nor RBP-4 were associated with peak BMD in young men.
Högström
Magnus
M
Sports Medicine, Department of Surgical and Perioperative Science, Umeå University, S-901 85 Umeå, Sweden.
Nordström
Anna
A
Nordström
Peter
P
D050153:Abdominal Fat / Q000378:metabolism*; D000328:Adult; D015415:Biomarkers; D015519:Bone Density / Q000502:physiology*; D001842:Bone and Bones / Q000378:metabolism; D015331:Cohort Studies; D024042:Collagen Type I / Q000378:metabolism; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D015233:Models, Statistical; D009765:Obesity / Q000378:metabolism*; D015675:Osteocalcin / Q000378:metabolism; D010024:Osteoporosis / Q000378:metabolism*; D010455:Peptides / Q000378:metabolism; D011237:Predictive Value of Tests; D054839:Retinol-Binding Proteins, Plasma / Q000378:metabolism*; D014801:Vitamin A / Q000097:blood*
D015415:Biomarkers; D024042:Collagen Type I; D010455:Peptides; C101326:RBP4 protein, human; D054839:Retinol-Binding Proteins, Plasma; C052929:collagen type I trimeric cross-linked peptide; D015675:Osteocalcin; D014801:Vitamin A