Introduction
Materials and Methods
Subjects
Study Protocol
Fat Mass Quantification
Blood Analysis, Data Analysis, Sample Size Estimation, and Statistical Analysis
Results
Before surgery | 3 months | 6 months | 12 months | 24 months | |
---|---|---|---|---|---|
BMI (kg/m2) | 40.6 ± 1.0 | 33.6 ± 0.9 | 29.1 ± 0.9 | 27.5 ± 1.0 | 27.4 ± 1.5 |
ΔBMI from baseline (kg/m2) | – | − 7.0 ± 0.5 | − 10.9 ± 0.9 | − 13.4 ± 1.2 | − 13.5 ± 1.5 |
%EWL | – | 46.4 ± 3.6 | 73.7 ± 5.5 | 88.6 ± 6.5 | 86.7 ± 9.3 |
%-LF | 13.0 ± 2.4 | 6.0 ± 1.7 | 3.9 ± 1.7 | 1.5 ± 0.3 | 2.3 ± 0.6 |
Decline in LF vs. before surgery (%) | – | 64.2 ± 4.7 | 74.8 ± 5.2 | 80.3 ± 4.5 | 79.2 ± 7.2 |
TLV (cm3) | 1725.5 ± 92.1 | 1348.6 ± 71.2 | 1266.5 ± 51.4 | 1426.1 ± 65.4 | 1424.6 ± 85.9 |
Before surgery | 3 months | 6 months | 12 months | 24 months | p values | |
---|---|---|---|---|---|---|
Total cholesterol (mmol/L) | 4.6 ± 0.2 | – | 3.9 ± 0.2 | 4.0 ± 0.2 | 4.4 ± 0.2 | p = 0.001a p = 0.023c p = 1.000d |
HDL cholesterol (mmol/L) | 1.3 ± 0.1 | – | 1.4 ± 0.1 | 1.5 ± 0.1 | 2.0 ± 0.1 | p = 0.965a p = 0.097c p < 0.001d |
Cholesterol/HDL ratio (mmol/L) | 3.7 ± 0.3 | – | 2.9 ± 0.1 | 2.7 ± 0.2 | 2.4 ± 0.1 | p = 0.027a p = 0.001c p < 0.001d |
LDL(mmol/L) | 2.9 ± 0.2 | – | 2.2 ± 0.2 | 2.1 ± 0.2 | 2.3 ± 0.2 | p = 0.001a p < 0.001c p = 0.152d |
Triglycerides (mmol/L) | 1.5 ± 0.3 | – | 0.9 ± 0.1 | 0.8 ± 0.1 | 1.1 ± 0.1 | p = 0.113a p = 0.091c p = 0.850d |
Fasting glucose (mmol/L) | 5.3 ± 0.2 | 4.7 ± 0.1 | 4.6 ± 0.1 | 4.7 ± 0.1 | – | p = 0.002a p = 0.001b p = 0.006c |
Fasting insulin (μU/mL) | 7.3 ± 1.0 | 2.9 ± 0.3 | 2.8 ± 0.7 | 2.5 ± 0.4 | – | p = 0.001a p = 0.007b p = 0.003c |
HOMA index | 1.7 ± 0.2 | 0.6 ± 0.1 | 0.6 ± 0.1 | 0.5 ± 0.1 | – | p < 0.001a p = 0.004b p = 0.002c |
Fat Mass Quantification
Reproducibility
Time Courses and Comparison of Exponential Decay Constants Between TLV, %-LF, SAT, and VAT
Non-linear regression coefficient ± SE, (p value) | |||
---|---|---|---|
A = (log)initial value | B = decay | A1 = slope of ascending process | |
HOMA | 0.4470 ± 0.1346 | − 0.3460 ± 0.0596 | 0.0402 ± 0.0066 |
(0.0019) | (< 0.001) | (< 0.001) | |
%-LF | 2.3328 ± 0.2156 | − 0.2084 ± 0.0336 | 0.0417 ± 0.0182 |
(< 0.001) | (< 0.001) | (0.0238) | |
TLV | 7.4392 ± 0.0505 | − 0.0839 ± 0.0088 | 48.5448 ± 3.5344 |
(< 0.001) | (< 0.001) | (< 0.001) | |
VAT volume | 1.5025 ± 0.1050 | − 0.0989 ± 0.0083 | 0.0492 ± 0.0106 |
(< 0.001) | (< 0.001) | (< 0.001) | |
SAT volume | 2.9518 ± 0.0540 | − 0.0999 ± 0.0065 | 0.2787 ± 0.0368 |
(< 0.001) | (< 0.001) | (< 0.001) |
A: %-LF | B: TLV | C: VAT volume | D: SAT volume | |
---|---|---|---|---|
Exponential decay constant (SD) | 0.21 ± 0.09 | 0.08 ± 0.02 | 0.10 ± 0.03 | 0.10 ± 0.02 |
B: 0.0012 | ||||
C: < 0.001 | C: 0.231 | |||
D: < 0.001 | D: 0.058 | D: 0.94 |
Associations Between %-LF and Blood Parameters
%-LF vs. Plasma Insulin, Plasma Glucose, and HOMA
Correlation | Regression coefficient ± SE (p value) | ||||
---|---|---|---|---|---|
Before surgery | 3 months | 6 months | 12 months | 24 months | |
A: %-LF vs. blood parameter | |||||
Total cholesterol | 0.066 ± 0.021 (0.007) | – | 0.068 ± 0.032 (0.059) | − 0.220 ± 0.336 (0.534) | 0.117 ± 0.164 (0.516) |
HDL cholesterol | − 0.004 ± 0.009 (0.687) | – | − 0.005 ± 0.017 (0.773) | 0.039 ± 0.083 (0.654) | 0.010 ± 0.123 (0.942) |
Cholesterol/HDL ratio | 0.058 ± 0.028 (0.057) | – | 0.056 ± 0.030 (0.091) | − 0.242 ± 0.251 (0.368) | 0.012 ± 0.121 (0.925) |
LDL | 0.070 ± 0.018 (0.002) | – | 0.079 ± 0.032 (0.035) | − 0.235 ± 0.317 (0.483) | 0.013 ± 0.153 (0.935) |
Triglycerides | 0.027 ± 0.029 (0.367) | – | 0.013 ± 0.017 (0.462) | − 0.081 ± 0.096 (0.427) | 0.205 ± 0.068 (0.040) |
Fasting glucose | 0.004 ± 0.015 (0.793) | − 0.006 ± 0.015 (0.690) | − 0.011 ± 0.015 (0.490) | − 0.103 ± 0.095 (0.303) | – |
Fasting insulin | 0.299 ± 0.077 (0.002) | 0.067 ± 0.042 (0.137) | − 0.051 ± 0.114 (0.662) | − 0.089 ± 0.376 (0.816) | – |
HOMA index | 0.073 ± 0.020 (0.003) | 0.013 ± 0.010 (0.192) | − 0.011 ± 0.022 (0.635) | − 0.035 ± 0.084 (0.681) | – |
B: %-LF difference from preoperative value vs. blood parameter difference from preoperative value | |||||
Total cholesterol | – | – | 0.027 ± 0.015 (0.106) | 0.007 ± 0.016 (0.684) | 0.044 ± 0.019 (0.083) |
HDL cholesterol | – | – | − 0.003 ± 0.011 (0.791) | − 0.006 ± 0.007 (0.426) | − 0.005 ± 0.010 (0.655) |
Cholesterol/HDL ratio | – | – | 0.031 ± 0.042 (0.485) | 0.017 ± 0.018\ (0.369) | 0.048 ± 0.029 (0.171) |
LDL | – | – | 0.024 ± 0.013 (0.091) | 0.022 ± 0.012\ (0.114) | 0.058 ± 0.019\ (0.036) |
Triglycerides | – | – | 0.022 ± 0.041 (0.612) | − 0.004 ± 0.017 (0.823) | − 0.006 ± 0.012 (0.655) |
Fasting glucose | – | 0.006 ± 0.019 (0.754) | 0.010 ± 0.019 (0.615) | 0.013 ± 0.014 (0.357) | – |
Fasting insulin | – | 0.148 ± 0.153 (0.351) | 0.159 ± 0.160 (0.340) | 0.337 ± 0.091 (0.003) | – |
HOMA index | – | 0.034 ± 0.040 (0.417) | 0.037 ± 0.040(0.371) | 0.082 ± 0.023 (0.004) | – |
%-LF vs. Blood Lipids
Associations Between VAT and Blood Parameters
VAT vs. Plasma Insulin, Plasma Glucose, and HOMA
Correlation | Regression coefficient ± SE (p value) | ||||
---|---|---|---|---|---|
Before surgery | 3 months | 6 months | 12 months | 24 months | |
A: VAT vs. blood parameter | |||||
Total cholesterol | 0.177 ± 0.130 (0.196) | – | 0.079 ± 0.192 (0.690) | 0.118 ± 0.320 (0.724) | 0.448 ± 0.139 (0.032) |
HDL cholesterol | − 0.030 ± 0.046 (0.533) | – | − 0.039 ± 0.092 (0.684) | − 0.051 ± 0.077 (0.529) | 0.227 ± 0.149 (0.202) |
Cholesterol/HDL ratio | 0.201 ± 0.154 (0.214) | – | 0.154 ± 0.184 (0.423) | 0.177 ± 0.240 (0.486) | − 0.053 ± 0.182 (0.784) |
LDL | 0.156 ± 0.125 (0.232) | – | 0.183 ± 0.216 (0.419) | 0.147 ± 0.302 (0.642) | 0.090 ± 0.227 (0.713) |
Triglycerides | 0.169 ± 0.146 (0.267) | – | 0.028 ± 0.095 (0.774) | 0.068 ± 0.090 (0.478) | 0.301 ± 0.110 (0.053) |
Fasting glucose | 0.067 ± 0.074 (0.378) | 0.122 ± 0.072 (0.112) | 0.052 ± 0.075 (0.503) | 0.144 ± 0.079 (0.093) | – |
Fasting insulin | 1.259 ± 0.449 (0.014) | 0.355 ± 0.215 (0.120) | 0.418 ± 0.553 (0.464) | − 0.070 ± 0.336 (0.838) | – |
HOMA index | 0.323 ± 0.111 (0.012) | 0.092 ± 0.045 (0.062) | 0.096 ± 0.108 (0.391) | 0.010 ± 0.076 (0.900) | – |
B: VAT difference from preoperative value vs. blood parameter difference from preoperative value | |||||
Total cholesterol | – | – | 0.092 ± 0.138 (0.518) | 0.166 ± 0.123 (0.218) | 0.031 ± 0.305 (0.923) |
HDL cholesterol | – | – | 0.074 ± 0.086 (0.416) | 0.022 ± 0.058 (0.720) | − 0.079 ± 0.106 (0.501) |
Cholesterol/HDL ratio | – | – | − 0.095 ± 0.336 (0.783) | 0.060 ± 0.158 (0.713) | 0.128 ± 0.392 (0.760) |
LDL | – | – | − 0.024 ± 0.119 (0.844) | 0.051 ± 0.123 (0.691) | 0.141 ± 0.354 (0.711) |
Triglycerides | – | – | 0.040 ± 0.328 (0.905) | 0.279 ± 0.095 (0.022) | 0.068 ± 0.128 (0.622) |
Fasting glucose | – | 0.045 ± 0.155 (0.777) | 0.150 ± 0.124 (0.250) | 0.092 ± 0.105 (0.398) | – |
Fasting insulin | – | 3.121 ± 0.945 (0.005) | 2.386 ± 0.898 (0.021) | 1.458 ± 0.915 (0.137) | – |
HOMA index | – | 0.805 ± 0.250 (0.006) | 0.604 ± 0.223 (0.019) | 0.386 ± 0.222 (0.108) | – |
VAT vs. Blood Lipids
Associations Between SAT and Blood Parameters
SAT vs. Plasma Insulin, Plasma Glucose, and HOMA
Correlation | Regression coefficient ± SE (p value) | ||||
---|---|---|---|---|---|
Before surgery | 3 months | 6 months | 12 months | 24 months | |
A: SAT vs. blood parameter | |||||
Total cholesterol | 0.009 ± 0.058 (0.881) | – | 0.022 ± 0.067 (0.752) | − 0.034 ± 0.144 (0.822) | 0.044 ± 0.090 (0.653) |
HDL cholesterol | 0.038 ± 0.017 (0.041) | – | 0.023 ± 0.030 (0.465) | 0.010 ± 0.035 (0.790) | 0.090 ± 0.048 (0.135) |
Cholesterol/HDL ratio | − 0.093 ± 0.064 (0.168) | – | 0.000 ± 0.064 (0.998) | − 0.010 ± 0.111 (0.929) | − 0.057 ± 0.058 (0.383) |
LDL | − 0.018 ± 0.055 (0.751) | – | 0.014 ± 0.075 (0.855) | − 0.037 ± 0.137 (0.793) | − 0.042 ± 0.078 (0.618) |
Triglycerides | − 0.039 ± 0.063 (0.548) | – | − 0.013 ± 0.032 (0.700) | − 0.002 ± 0.042 (0.971) | 0.003 ± 0.065 (0.963) |
Fasting glucose | 0.004 ± 0.0032 (0.908) | − 0.021 ± 0.026 (0.429) | − 0.001 ± 0.027 (0.968) | 0.056 ± 0.026 (0.055) | – |
Fasting insulin | − 0.122 ± 0.233 (0.608) | 0.038 ± 0.080 (0.641) | 0.088 ± 0.198 (0.663) | − 0.093 ± 0.113 (0.425) | – |
HOMA index | − 0.024 ± 0.059 (0.695) | 0.005 ± 0.018 (0.783) | 0.019 ± 0.039 (0.639) | − 0.013 ± 0.026 (0.629) | – |
B: SAT difference from preoperative value vs. blood parameter difference from preoperative value | |||||
Total cholesterol | – | – | − 0.059 ± 0.044 (0.208) | − 0.001 ± 0.044 (0.977) | 0.004 ± 0.067 (0.954) |
HDL cholesterol | – | – | 0.049 ± 0.027 (0.098) | 0.006 ± 0.018 (0.772) | 0.017 ± 0.023 (0.501) |
Cholesterol/HDL ratio | – | – | − 0.161 ± 0.105 (0.158) | − 0.019 ± 0.050 (0.715) | − 0.016 ± 0.087 (0.863) |
LDL | – | – | − 0.040 ± 0.039 (0.339) | − 0.006 ± 0.040 (0.887) | − 0.017 ± 0.079 (0.838) |
Triglycerides | – | – | − 0.089 ± 0.110 (0.439) | 0.041 ± 0.042 (0.370) | 0.031 ± 0.025 (0.283) |
Fasting glucose | – | 0.109 ± 0.082 (0.202) | 0.040 ± 0.053 (0.461) | 0.073 ± 0.033 (0.046) | – |
Fasting insulin | – | − 0.279 ± 0.700 (0.697) | − 0.220 ± 0.463 (0.643) | − 0.035 ± 0.362 (0.923) | – |
HOMA index | – | − 0.047 ± 0.184 (0.803) | − 0.045 ± 0.116 (0.705) | 0.014 ± 0.089 (0.879) | – |