TY - JOUR
T1 - Gender, age, body mass index, and IGF-I individually and jointly determine distinct GH dynamics
T2 - Analyses in one hundred healthy adults
AU - Veldhuis, Johannes D.
AU - Roelfsema, Ferdinand
AU - Keenan, Daniel M.
AU - Pincus, Steven
N1 - Funding Information:
This work was supported in part via the Center for Translational Science Activities Grant 1 UL 1 RR024150 from the National Center for Research Resources (Rockville, MD) and AG019695 and AG029362 from the National Institutes of Health (Bethesda, MD). The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institute on Aging or the National Institutes of Health.
PY - 2011/1
Y1 - 2011/1
N2 - Background: GH secretion is quantifiable as mean, peak, and nadir GH concentrations; degree of irregularity (approximate entropy); and spikiness (brief staccato-like fluctuations). Hypothesis: Distinct GH dynamics reflect relatively distinct (combinations of) subject variables, such as gender, age, body mass index (BMI), and IGF-I concentrations. Location: The study took place at a clinical translational research unit. Subjects: Subjects included 100 healthy adults ages 20-77 yr (59 women and 41 men), BMI 18-42 kg/m2, and IGF-I 9.2-38 nmol/liter. Measures: Immunofluorometric GH assay was done on 10-min samples collected for 24 h. Results: Stepwise forward-selection multivariate regression analysis revealed that mean GH concentrations were simultaneously determined (overall r=0.36; P<0.001) by gender (higher in women, P< 0.001), BMI (negatively, P<0.001), and IGF-I (positively, P<0.001). Peak GH levels were influenced (r= 0.28) by both BMI (P < 0.001) and IGF-I (P < 0.001). Nadir GH values were jointly affected by gender (higher in women, P = 0.005) and BMI (negatively, P = 0.001). GH approximate entropy was triply defined (r=0.29) by gender (greater irregularity in women, P=0.001), age (P=0.022), and BMI (P=0.008) and dually (r=0.25) by gender (P=0.0001) and BMI (P=0.017) if sex steroids were included. GH spikiness was determined (r=0.29) by gender (higher in women, P=0.0016) and BMI (positively, P=0.0002). Conclusion: In healthy adults, combinations of gender, age, BMI, and IGF-I specify distinct GH dynamics, thus requiring balanced representation of these variables in comparative GH studies.
AB - Background: GH secretion is quantifiable as mean, peak, and nadir GH concentrations; degree of irregularity (approximate entropy); and spikiness (brief staccato-like fluctuations). Hypothesis: Distinct GH dynamics reflect relatively distinct (combinations of) subject variables, such as gender, age, body mass index (BMI), and IGF-I concentrations. Location: The study took place at a clinical translational research unit. Subjects: Subjects included 100 healthy adults ages 20-77 yr (59 women and 41 men), BMI 18-42 kg/m2, and IGF-I 9.2-38 nmol/liter. Measures: Immunofluorometric GH assay was done on 10-min samples collected for 24 h. Results: Stepwise forward-selection multivariate regression analysis revealed that mean GH concentrations were simultaneously determined (overall r=0.36; P<0.001) by gender (higher in women, P< 0.001), BMI (negatively, P<0.001), and IGF-I (positively, P<0.001). Peak GH levels were influenced (r= 0.28) by both BMI (P < 0.001) and IGF-I (P < 0.001). Nadir GH values were jointly affected by gender (higher in women, P = 0.005) and BMI (negatively, P = 0.001). GH approximate entropy was triply defined (r=0.29) by gender (greater irregularity in women, P=0.001), age (P=0.022), and BMI (P=0.008) and dually (r=0.25) by gender (P=0.0001) and BMI (P=0.017) if sex steroids were included. GH spikiness was determined (r=0.29) by gender (higher in women, P=0.0016) and BMI (positively, P=0.0002). Conclusion: In healthy adults, combinations of gender, age, BMI, and IGF-I specify distinct GH dynamics, thus requiring balanced representation of these variables in comparative GH studies.
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U2 - 10.1210/jc.2010-1669
DO - 10.1210/jc.2010-1669
M3 - Article
C2 - 20926525
AN - SCOPUS:78650887936
SN - 0021-972X
VL - 96
SP - 115
EP - 121
JO - Journal of Clinical Endocrinology and Metabolism
JF - Journal of Clinical Endocrinology and Metabolism
IS - 1
ER -