Age-related changes in body composition, hydroxyproline, and creatinine excretion in normal women.
We have made a cross-sectional study of relationships among age, whole body bone mineral content (WBBMC), and non-bone lean body mass (NBLBM) measured by dual energy X-ray absorptiometry (DXA), and daily excretion of hydroxyproline (OHP) and creatinine (Cr) in a group of normal women. WBBMC fell with age from the 6th decade, whereas NBLBM was almost constant. Creatinine excretion fell with age from the 5th decade until the 9th, to a much greater degree than NBLBM, reaching a nadir in the 8th decade. Daily excretion of hydroxyproline showed a peak in the 6th decade and fell moderately thereafter. The greater fall of creatinine compared with hydroxyproline resulted in rising OHP/Cr ratios with advancing age, in contrast to the pattern of hydroxyproline excretion. The use of creatinine as a correction for urine dilution or for lean body mass (LBM) in assays for markers of bone turnover must therefore be viewed with caution.
Worsfold
M
M
Charles Salt Research Centre, Robert Jones & Agnes Hunt Hospital, Oswestry, Shropshire, UK SY10 7AG.
Davie
M W
MW
Haddaway
M J
MJ
D015502:Absorptiometry, Photon; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D001823:Body Composition / Q000502:physiology*; D015519:Bone Density; D001842:Bone and Bones / Q000502:physiology*; D003401:Creatine / Q000652:urine*; D005260:Female; D006801:Humans; D006909:Hydroxyproline / Q000652:urine*; D008875:Middle Aged
D003401:Creatine; D006909:Hydroxyproline