Table 5.
Generation of cut-offs for SMI (corresponding to BMI thresholds) based on FFMI.
| BMI (kg/m2) |
FMIDXA (kg/m2) (Kelly et al., 2009) |
FFMIDXA (kg/m2) (Modified according to Kelly et al., 2009) |
SMIMRI (kg/m2) (1.5 T Siemens Avanto MRI Scanner) |
SMIBIA_median (kg/m2) (mBCA 515, Seca) |
SMIBIA_-2SDs (kg/m2) (mBCA 515, Seca) |
|
|---|---|---|---|---|---|---|
| Caucasian men | <18.5 | <2.9 | 15.6 | 8.6 | >7.6 | |
| >25 | >6.0 | 19.0 | 9.85 | 9.7 | >8.7 | |
| >30 | >8.9 | 21.1 | 10.71 | 10.5 | >9.5 | |
| >35 | >11.9 | 23.1 | 12.15 | 11.4 | >10.3 | |
| >40 | >15.0 | 25.0 | 13.67 | 12.2 | >11.2 | |
| Caucasian women | <18.5 | <4.9 | 13.6 | 6.65 | 6.7 | >5.7 |
| >25 | >9.2 | 15.8 | 7.49 | 7.7 | >6.8 | |
| >30 | >12.9 | 17.1 | 8.15 | 8.5 | >7.6 | |
| >35 | >16.8 | 18.2 | 8.99 | 9.3 | >8.4 | |
| >40 | >20.6 | 19.4 | 9.74 | 10.1 | >9.2 |
BMI, body mass index; FMIDXA, fat mass index by dual X-ray absorptiometry (QDR 4500A fan beam densitometer (Hologic, Inc., Bedford, MA, Hologic Discovery software version 12.1)); FFMIDXA, fat-free mass index by dual X-ray absorptiometry; SMIMRI, skeletal muscle mass index by magnetic resonance imaging calculated by stepwise regression analysis (n = 410, 219 women (age: 38 ± 13 years, BMI: 27.7 ± 6.5 kg/m2) and 191 men (age: 41 ± 14 years, BMI: 27.7 ± 5.0 kg/m2) (detailed description of the segmentation procedure given elsewhere (Schautz et al., 2012)); SMIBIA_median, skeletal muscle mass index by bioelectrical impedance analysis given as median calculated by linear regression analysis (n = 529, 264 women (27 ± 6 years, BMI: 23.9 ± 3.6 kg/m2) and 265 men (28 ± 6 years, BMI: 25.2 ± 3.2 kg/m2) (detailed description of the BIA measurement procedure given elsewhere (Bosy-Westphal et al., 2017)); SMIBIA_-2SDs, skeletal muscle mass index by bioelectrical impedance analysis given as 2 SDs below the sex-specific mean calculated as linear regression analysis.