Body composition during GH replacement in adults - methodological variations with respect to gender.
OBJECTIVE
Men with growth hormone deficiency (GHD) may be more sensitive to GH treatment than women in terms of changes in body composition. We have studied whether age, body-mass index (BMI) and the different types of methodology used to assess body composition may explain these differences.


METHODS
Forty-four men and forty-four women with GHD, closely matched for age and BMI, were studied before and after 6 months of GH replacement. The dose of GH was individually adjusted. Body composition was assessed by measurements of potassium-40, total body nitrogen (TBN), tritiated water dilution, dual-energy X-ray absorptiometry (DXA) and bioelectrical impedance analysis (BIA). Four- and five-compartment models for body composition were also calculated.


RESULTS
The total daily dose of GH was similar in men and women at 6 months. Serum insulin-like growth factor-I (IGF-I) was higher in men than women at baseline and after 6 months of treatment (P = 0.01, paired t-test). The increment was, however, similar. In women, GH treatment reduced body weight and increased TBN. In both men and women, total body water and body cell mass increased, while total body fat (BF) mass decreased. At baseline, mean total BF varied considerably depending on the methodology used, with the highest value obtained from DXA. The changes in BF were, however, less dependent on the methodology, but DXA and BIA demonstrated the largest inconsistency between men and women.


CONCLUSIONS
These results suggest that gender differences in body composition in response to GH treatment are small, if adjustments are made for baseline factors such as age, BMI and dose of GH. Different methods of body composition measurements produce different results, but changes in response to GH administration are less inconsistent.
Research Centre for Endocrinology and Metabolism, Sahlgrenska University Hospital, Göteborg, Sweden. josef.koranyi@medic.gu.se
Josef
J
Koranyi
Ingvar
I
Bosaeus
Magne
M
Alpsten
Bengt-Ake
BA
Bengtsson
Gudmundur
G
Johannsson
D015502:Absorptiometry, Photon; D000328:Adult; D000368:Aged; D001823:Body Composition; D015992:Body Mass Index; D001834:Body Water; D017097:Electric Impedance; D005260:Female; D020249:Hormone Replacement Therapy / Q000379:methods*; D019382:Human Growth Hormone / Q000008:administration & dosage* / Q000172:deficiency*; D006801:Humans; D007018:Hypopituitarism / Q000188:drug therapy; D007334:Insulin-Like Growth Factor I / Q000032:analysis; D008297:Male; D008875:Middle Aged; D009584:Nitrogen / Q000032:analysis; D010911:Pituitary Neoplasms / Q000150:complications; D011188:Potassium / Q000032:analysis; D011194:Potassium Isotopes / Q000032:analysis; D012727:Sex Characteristics; D014316:Tritium
D011194:Potassium Isotopes; D014316:Tritium; D019382:Human Growth Hormone; D007334:Insulin-Like Growth Factor I; D009584:Nitrogen; D011188:Potassium