Lean body mass: the development and validation of prediction equations in healthy adults.
BACKGROUND
There is a loss of lean body mass (LBM) with increasing age. A low LBM has been associated with increased adverse effects from prescribed medications such as chemotherapy. Accurate assessment of LBM may allow for more accurate drug prescribing. The aims of this study were to develop new prediction equations (PEs) for LBM with anthropometric and biochemical variables from a development cohort and then validate the best performing PEs in validation cohorts.


METHODS
PEs were developed in a cohort of 188 healthy subjects and then validated in a convenience cohort of 52 healthy subjects. The best performing anthropometric PE was then compared to published anthropometric PEs in an older (age≥50 years) cohort of 2287 people. Best subset regression analysis was used to derive PEs. Correlation, Bland-Altman and Sheiner & Beal methods were used to validate and compare the PEs against dual X-ray absorptiometry (DXA)-derived LBM.


RESULTS
The PE which included biochemistry variables performed only marginally better than the anthropometric PE. The anthropometric PE on average over-estimated LBM by 0.74 kg in the combined cohort. Across gender (male vs. female), body mass index (<22, 22-<27, 27-<30 and ≥30 kg/m2) and age groups (50-64, 65-79 and ≥80 years), the maximum mean over-estimation of the anthropometric PE was 1.36 kg.


CONCLUSIONS
A new anthropometric PE has been developed that offers an alternative for clinicians when access to DXA is limited. Further research is required to determine the clinical utility and if it will improve the safety of medication use.
Aged and Extended Care Services, Level 8B Main Building, The Queen Elizabeth Hospital, Central Adelaide Local Health Network, 21 Woodville Road, 5011 Woodville South, SA, Australia. solomon.yu@adelaide.edu.au.
Solomon
S
Yu
Thavarajah
T
Visvanathan
John
J
Field
Leigh C
LC
Ward
Ian
I
Chapman
Robert
R
Adams
Gary
G
Wittert
Renuka
R
Visvanathan
D015502:Absorptiometry, Photon; D050154:Adiposity / Q000502:physiology; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology; D000886:Anthropometry; D001823:Body Composition; D015992:Body Mass Index; D015331:Cohort Studies; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D011237:Predictive Value of Tests; D012044:Regression Analysis; D015203:Reproducibility of Results; D055948:Sarcopenia / Q000503:physiopathology; D013851:Thinness / Q000503:physiopathology*; D055815:Young Adult