Serum Insulin-Like Growth Factor I and Its Relating Factors in Healthy Korean Adults Aged over 40 Years

ABSTRACT

BACKGROUND: There is a clinical need for a reference value based on healthy adults in Korea. The aim of this study was to define IGF-1 concentration in healthy Korean adults and to investigate the factors relative to IGF-1 level. METHODS: By reviewing the medical records of a hospital in Korea, healthy 112 men and 109 women aged over 40 years were studied. We determined the serum IGF-1 levels of both groups according to age, sex, health behaviors, lipid profile, bone mineral density, serum albumin, waist circumference, body mass index, total testosterone, and FSH. RESULTS: IGF-1 had no sexual difference in any age group (258.7+/-84.3 ng/mL for men, 263.7+/-86.8 ng/mL for women), but correlated negatively with age (r=-0.43 and -0.35 for men and women, respectively). The mean decline was 49.6 ng/mL and 43.9 ng/mL per 10 years for men and women, respectively. IGF-1 correlated positively with serum albumin, total cholesterol, and bone mineral density of spine and femur neck. The multiple regression analysis showed that the most powerful factors influencing IGF-1 level was serum albumin (R2; 0.13) followed by age, bone mineral density of femur neck, and total cholesterol. CONCLUSION: We present a reference value for IGF-1 in healthy Korean adults aged over 40 years. The most powerful factor influencing IGF-1 level was serum albumin.