Isojima T.,Growth Science |
Isojima T.,University of Tokyo |
Shimatsu A.,Growth Science |
Shimatsu A.,Clinical Research Institute |
And 13 more authors.
Endocrine Journal | Year: 2012
Measurements of insulin-like growth factor-I (IGF-I) are useful not only for diagnosis and management of patients with growth hormone (GH)-related disorders but also for assessing nutritional status. We reported populationbased references of serum IGF-I in 1996. However, they did not properly reflect data in the transition period from puberty to maturity. The aim of the present study was to re-establish a set of normative data for IGF-I for the Japanese population. The study included 1,685 healthy Japanese subjects (845 males, 840 females) from 0 to 83 years old. Subjects suffering from diseases that could affect IGF-I levels were excluded. Obese or extremely thin adult subjects were also excluded. IGF-I concentrations were determined by commercially available immunoradiometric assays. The reference intervals were calculated using the LMS method. Median IGF-I levels reached 310 ng/mL in males at the age of 14 years and 349 ng/mL in females at the age of 13 years, falling to 124 ng/mL and 103 ng/mL, respectively, by the age of 70 years. The mean pretreatment IGF-1 SD scores in patients with severe GH deficiency (GHD) obtained from the database of the Foundation for Growth Science and from clinical studies for adult GHD were -2.1±1.6 and -4.9±2.5, respectively. The present study established age- and gender-specific normative IGF-I data for the Japanese population and showed the utility of these references for screening patients with severe GHD. © The Japan Endocrine Society.