2 There was considerable scatter in the data, but in both lean and obese individuals the relative β cell volume, a surrogate for mass, was about 30 70% of nondiabetic controls.
To distinguish between cystatin C (CysC) and creatinine (Cr) as markers of estimated glomerular filtration rate (eGFR) in preterm infants and to correlate eGFR with total kidney volume (TKV) as a surrogate of nephron mass.
Using total length as a surrogate for body mass, we did not find significant relationships between total length and either current temperature or change in temperature over time.
Two QTLs near D11Mit41 on Chr 11 and D14Mit107 on Chr 14, respectively, were significantly linked to carcass weights (surrogate lean body mass).
An algorithm for dose was developed and used the significant genotypes together with age, sex (as a surrogate for body mass) and additional drugs.
Creatinine production, as a surrogate of muscle mass, was calculated by the sum of 24h urine creatinine excretion and metabolized creatinine.
Furthermore, in a longitudinal study of 121,762 patients receiving hemodialysis, declining serum creatinine (a surrogate for muscle mass) over time was a stronger predictor of mortality than was weight loss, also suggesting that the protective effect of high BMI is a result of muscle mass, not fat mass (49).
Most of the variance of obesity-related anthropometrics is captured by BMI, and all these indices are similarly strong surrogates of fat mass [ 33].
The associations between FMI and fat mass surrogates (TSF, MAC) with obestatin observed in our study were insignificant in multivariable models and therefore were not independent.
Fitness surrogates (survival and mass change) for the laboratory experiments were analyzed using LMMs following the same logic as explained above for the field experiments (see hypotheses 1 3 above).
Fitness surrogates (survival and mass change) were analyzed with (generalized) linear mixed effect models (G LMMs in the lme4 package in R (R Development Core Team 2009; Bates et al. 2014).
