Relation between fibroblast growth factor-23, body weight and bone mineral density in elderly men.
CONCLUSIONS
We evaluated the relation between serum FGF23 and bone mineral density (BMD) in a community-based cohort of elderly men. There was a weak correlation between FGF23 and BMD, which was primarily dependent on body weight.


BACKGROUND
FGF23 is a hormonal factor produced in bone and regulates serum levels of phosphate (Pi) and vitamin D. FGF23 over-expression is associated with skeletal abnormalities, including rickets/osteomalacia. The relation between FGF23 and Bone Mineral Density (BMD) in the community remains unexplored.


METHODS
We employed a large, population-based cohort of 3014 Swedish men aged 69-80 years, without known renal disease. BMD was measured with dual X-ray absorptiometry (DXA) in the hip and lumbar spine. Serum intact FGF23 was analyzed with a two-site monoclonal ELISA.


RESULTS
There was a weak but significant correlation between FGF23 and BMD in femoral neck (r = 0.04, p < 0.05), femoral trochanter (r = 0.05, p = 0.004), total hip (r = 0.06, p = 0.0015) and lumbar spine (r = 0.07, p = 0.0004). The correlations remained significant when adjusting for biochemical covariates (Pi, calcium, PTH, 25(OH)D and renal function). However, the association became insignificant in all regions when adjusting for established confounding variables including age, height, weight and smoking. Further analysis confirmed a significant correlation between FGF23 and body weight (r = 0.13, p < 0.0001).


CONCLUSIONS
The weak correlation between FGF23 and BMD in elderly male subjects is mainly due to an association between FGF23 and body weight. Therefore, FGF23 may not play a significant role in the hormonal regulation of BMD.
Marsell
R
R
Department of Surgical Sciences, Uppsala University Hospital, Uppsala, Sweden. richard.marsell@surgsci.uu.se
Mirza
M A I
MA
Mallmin
H
H
Karlsson
M
M
Mellström
D
D
Orwoll
E
E
Ohlsson
C
C
Jonsson
K B
KB
Ljunggren
O
O
Larsson
T E
TE
D015502:Absorptiometry, Photon; D000368:Aged; D000369:Aged, 80 and over; D001835:Body Weight / Q000502:physiology*; D015519:Bone Density / Q000502:physiology*; D005269:Femur / Q000000981:diagnostic imaging; D005272:Femur Neck / Q000000981:diagnostic imaging; D000089703:Fibroblast Growth Factor-23; D005346:Fibroblast Growth Factors / Q000097:blood*; D006801:Humans; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging; D008297:Male; D011446:Prospective Studies; D013548:Sweden
C000717427:FGF23 protein, human; D005346:Fibroblast Growth Factors; D000089703:Fibroblast Growth Factor-23