The insulin-like growth factor axis and plasma lipid levels in the elderly

• Published in: The journal of clinical endocrinology and metabolism Vol. 83; no. 2; pp. 499 - 502
• Main Authors: CEDA, G. P, DALL'AGLIO, E, MAGNACAVALLO, A, VARGAS, N, FONTANA, V, MAGGIO, M, VALENTI, G, LEE, P. D. K, HINTZ, R. L, HOFFMAN, A. R
• Format: Journal Article
• Language: English
• Published: Bethesda, MD Endocrine Society 01-02-1998
• Subjects: Aged; Aged, 80 and over; Aging - blood; Apolipoprotein A-I - metabolism; Biological and medical sciences; Body Mass Index; Cholesterol, HDL - blood; Disorders of blood lipids. Hyperlipoproteinemia; Female; Human Growth Hormone - physiology; Humans; Insulin-Like Growth Factor Binding Protein 3 - blood; Insulin-Like Growth Factor I - metabolism; Insulin-Like Growth Factor II - metabolism; Lipids - blood; Male; Medical sciences; Metabolic diseases; Middle Aged; Regression Analysis; Sex Characteristics; Triglycerides - blood; Italy; Europe; Human; Cholesterolemia; Sex; Apolipoprotein AI; Insulin like growth factor 1; Insulin like growth factor 2; Blood plasma; Assay; Insulin like growth factor binding protein; Body mass index; Cholesterol HDL; Adult; Elderly; Age; Comparative study
• ISSN: 0021-972X; 1945-7197
• DOI: 10.1210/jc.83.2.499

The activity of the hypothalamic-GH-insulin-like growth factor (IGF) network declines with age. It has recently been shown that increased cardiovascular mortality occurs in adults with GH deficiency. As hypercholesterolemia is common in GH-deficient adults, and because there is experimental evidence that GH may play a role in regulating plasma cholesterol, we decided to investigate the activity of the GH-IGF axis in an elderly population by measuring serum IGF-I, IGF-II, and IGF-binding protein-3 (IGFBP-3) levels and to study their relationship with blood lipid levels. One hundred and thirty-two elderly subjects, 52 men and 80 women, were studied (age range, 60-91 yr). Men had significantly lower levels of IGFBP-3, high density lipoprotein cholesterol (HDL-C) and apoprotein A1 (ApoA1) compared to the women, whereas IGF-I and IGF-II were only slightly lower. Using linear regression analysis, we observed an inverse relationship of age with IGF-I (r = -0.35; P < 0.001), IGF-II (r = 0.40; P < 0.001), IGFBP-3 (r = 0.52; P < 0.001), body mass index, and lipid levels. Univariate regression analysis showed a strong and positive correlation of both IGF-I and IGFBP-3 with HDL-C and ApoA1. Partial correlation analysis, after adjustment for age and body mass index, showed that IGFBP-3 and IGF-II were still significantly and positively related to HDL-C and ApoA1. Furthermore, a strong association was documented among IGF-I, IGF-II, and IGFBP-3. These data demonstrate that even in an elderly population, further aging is accompanied by a progressive decline in circulating IGF-I, IGF-II, and IGFBP-3, suggesting a continuing diminution of the GH-IGF axis throughout aging. Moreover, the strong correlation between HDL-C and an index of GH secretion, such as IGFBP-3, suggests that GH might play an important role in lipid metabolism in healthy elderly subjects.