Table 1.
Baseline characteristics of study subjects stratified by BMI and GH status (n = 102)
| Normal weight | Obese GHS | Obese GHD | P value | P value adjusted for gender | |
|---|---|---|---|---|---|
| n | 33 | 55 | 14 | ||
| Age (yr) | 44.0 (28.5–49.0) | 43.0 (36.0–48.0) | 45.0 (40.0–47.75) | 0.68 | |
| Gender, no. of males (%) | 21 (64) | 28 (51) | 11 (78) | 0.12 | |
| Race, n (%) | 0.32 | 0.16 | |||
| Caucasian | 21 (64) | 26 (47) | 8 (57) | ||
| Not Caucasian | 12 (36) | 29 (53) | 6 (43) | ||
| Tobacco (pack years) | 5.3 ± 1.8 | 8.6 ± 1.9 | 2.7 ± 1.5 | 0.21 | 0.10 |
| Blood pressure (mm Hg) | |||||
| Systolic | 118 ± 2 | 119 ± 2 | 126 ± 4 | 0.20 | 0.008 |
| Diastolic | 74 ± 1 | 75 ± 1 | 78 ± 3 | 0.06 | 0.0005 |
| Body composition | |||||
| Height (cm) | 173.2 ± 1.6 | 169.7 ± 1.1 | 174.5 ± 3.0 | 0.02 | <0.0001 |
| BMI (kg/m2) | 22.5 ± 0.3 | 37.2 ± 0.8a | 40.7 ± 2.3b | <0.0001 | <0.0001 |
| SAT by abdominal CT (cm2) | 129 ± 11 | 464 ± 20a | 527 ± 44b | <0.0001 | <0.0001 |
| VAT by abdominal CT (cm2) | 51 ± 7 | 177 ± 11a | 216 ± 16b | <0.0001 | <0.0001 |
| % Total fat by DEXA | 19.1 ± 1.3 | 35.5 ± 1.2a | 34.1 ± 2.0b | <0.0001 | <0.0001 |
| Metabolic parameters | |||||
| Total cholesterol (mg/dl) | 174 ± 6 | 183 ± 4 | 181 ± 10 | 0.67 | 0.42 |
| HDL cholesterol (mg/dl) | 58 ± 3 | 45 ± 2a | 44 ± 2b | <0.0001 | 0.0001 |
| LDL cholesterol (mg/dl) | 101 ± 5 | 115 ± 4 | 117 ± 8 | 0.12 | 0.06 |
| Triglycerides (mg/dl) | 75 ± 7 | 126 ± 11a | 134 ± 22b | 0.01 | 0.03 |
| Fasting glucose (mg/dl) | 86 ± 2 | 95 ± 3 | 94 ± 2 | 0.10 | 0.05 |
| 2-h glucose on OGTT (mg/dl) | 98 ± 7 | 128 ± 7a | 122 ± 8 | 0.03 | 0.07 |
| HbA1c (%) | 5.5 ± 0.04 | 5.8 ± 0.07a | 5.7 ± 0.09 | 0.006 | 0.009 |
| Fasting insulin (μIU/ml) | 3.1 ± 0.4 | 8.9 ± 1.0a | 8.9 ± 1.5b | <0.0001 | <0.0001 |
| Basal GH (μg/liter) | 0.8 ± 0.2 | 0.1 ± 0.03a | 0.1 ± 0.06b | 0.0005 | 0.0007 |
| Peak GH on stimulation test (μg/liter) | 44.7 ± 4.9 | 10.3 ± 1.0a | 2.8 ± 0.3b,c | <0.0001 | <0.0001 |
| IGF-I (μg/liter)d | 93 ± 8 | 77 ± 5 | 58 ± 7b | 0.02 | 0.003 |
Relative GHD is defined as peak stimulated GH of 4.2 μg/liter or less on standard GHRH-arginine stimulation test. Results are presented as mean ± sem except for age, which is presented as median (IQR). Statistical significance was determined by ANOVA, followed by Tukey-Kramer and Student’s t test for significant ANOVA. P value for ANOVA and ANOVA adjusted for gender are reported. Age is reported as median (IQR) with analysis provided by nonparametric Wilcoxon rank sum test. For determination of significance for race, a χ2 test was performed for Caucasian or not. DEXA, dual x-ray absorptiometry.
P < 0.05 for obese GHS vs. normal weight.
P < 0.05 for obese GHD vs. normal weight.
P < 0.05 for obese GHD vs. obese GHS.
Corresponding IGF-I sd scores for the three groups are: normal weight, −0.6 ± 0.2; obese GHS, −0.9 ± 0.1; and obese GHD, −1.3 ± 0.2.