Effects of GH in women with abdominal adiposity: a 6-month randomized, double-blind, placebo-controlled trial

Abstract

Objective: Abdominal adiposity is associated with increased cardiovascular risk and decreased GH secretion. The objective of our study was to determine the effects of GH on body composition and cardiovascular risk markers in abdominally obese women.

Materials and methods: In this randomized, double-blind, placebo-controlled study, 79 obese premenopausal women received GH vs placebo for 6 months. Primary endpoints were i) total abdominal (total abdominal adipose tissue, TAT) fat by computed tomography (CT) (body composition) and ii) high-sensitivity C-reactive protein (hsCRP) (cardiovascular risk marker). Body composition was assessed by CT, dual-energy X-ray absorptiometry, and proton MR spectroscopy. Serum cardiovascular risk markers, carotid intima-media thickness, and endothelial function were measured.

Results: Mean 6-month GH dose was 1.7±0.1 mg/day, resulting in a mean IGF1 SDS increase from -1.7±0.08 to -0.1±0.3 in the GH group. GH administration decreased TAT and hsCRP compared with placebo. In addition, it increased thigh muscle mass and lean body mass and decreased subcutaneous abdominal and trunk fat, tissue plasminogen activator, apoB, and apoB/low-density lipoprotein compared with placebo. Visceral adipose tissue (VAT) decreased and intramyocellular lipid increased within the GH group. Six-month change in IGF1 levels was negatively associated with 6-month decrease in TAT and VAT. One subject had a 2 h glucose >200 mg/ml at 3 months; four subjects, three of whom were randomized to GH, had 2 h glucose levels >200 mg/ml at the end of the study.

Conclusion: GH administration in abdominally obese premenopausal women exerts beneficial effects on body composition and cardiovascular risk markers but is associated with a decrease in glucose tolerance in a minority of women.

Trial registration: ClinicalTrials.gov NCT00131378.

Figure 1

Flow diagram of randomized trial of GH versus placebo according to CONSORT guidelines.

Figure 2

IGF-1 levels (A) and IGF-1 standard deviation scores (SDS) (B) of subjects randomized to GH. Open diamonds represent mean values. Conversion to SI units: IGF-1 (ng/mL) multiply by 0.131 for nmol/L

Figure 3

Abdominal CT at the level of L4 in a study subject before (A) and after (B) 6 months of GH administration showing reduction of abdominal fat (dark grey areas).

Figure 4

Mean (± SEM) change in hsCRP over 6 months of GH administration versus placebo. *, p< 0.05 vs. placebo. Conversion to SI units: hsCRP (mg/L) multiply by 9.524 for nmol/L

Figure 5

Regression analysis of baseline fasting glucose on 6-month change in 2-hour glucose within the GH group. Baseline fasting glucose predicted 2-hour glucose after 6 months of GH administration. Conversion to SI units: glucose (mg/L) multiply by 0.0555 for mmol/L

Figure 6

Regression analysis of 6-month change in IGF-1 on 6-month change in visceral adipose tissue (VAT) within the GH group. 6-month change in IGF-1 predicted 6-month change in VAT.