title: Insulin-like growth factor-1 is a mediator of age-related decline of bone health status in men.
abstract: OBJECTIVE
  The role of insulin-like growth factor-1 (IGF-1) in bone health in men is debatable. This study aimed to determine whether IGF-1 is a mediator in age-related decline of bone health status measured by calcaneal speed of sound (SOS) in Malaysian men.
  
  
  METHODS
  The study recruited 279 Chinese and Malay men. Their demographic data, weight, height, calcaneal SOS were taken and fasting blood was collected for total testosterone, sex-hormone binding globulin and IGF-1 assays. The associations between the studied variables were assessed using multiple linear regression (MLR) analysis. Mediator analysis was performed using Sobel test.
  
  
  RESULTS
  There was a significant and parallel decrease of IGF-1 and SOS with age (p < 0.05). Serum IGF-1 was significantly and positively associated with SOS (p < 0.05) but after further adjustment for age, the significance was lost (p > 0.05). The strength of the association between age and SOS decreased after adjusting for IGF-1 level but it remained significant (p < 0.05). Sobel test revealed that IGF-1 was a significant partial mediator in the relationship between age and SOS (z = -4.3).
  
  
  CONCLUSIONS
  Serum IGF-1 is a partial mediator in the age-related decline of bone health in men as determined by calcaneal ultrasound. A prospective study should be performed to validate this relationship.
authors.affiliation: Department of Pharmacology .
authors.forename: Kok-Yong
authors.initials: KY
authors.lastname: Chin
authors.forename: Soelaiman
authors.initials: S
authors.lastname: Ima-Nirwana
authors.forename: Isa Naina
authors.initials: IN
authors.lastname: Mohamed
authors.forename: Mohamad
authors.initials: M
authors.lastname: Hanapi Johari
authors.forename: Fairus
authors.initials: F
authors.lastname: Ahmad
authors.forename: Elvy Suhana
authors.initials: ES
authors.lastname: Mohamed Ramli
authors.forename: Wan Zurinah
authors.initials: WZ
authors.lastname: Wan Ngah
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology; D015519:Bone Density / Q000502:physiology*; D002111:Calcaneus / Q000000981:diagnostic imaging / Q000502:physiology*; D003430:Cross-Sectional Studies; D006304:Health Status; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D010024:Osteoporosis / Q000097:blood*; D012738:Sex Hormone-Binding Globulin / Q000378:metabolism; D013739:Testosterone / Q000097:blood; D014463:Ultrasonography; D055815:Young Adult
chemical_list: D012738:Sex Hormone-Binding Globulin; D013739:Testosterone; D007334:Insulin-Like Growth Factor I
keywords: Bone; calcaneus; insulin-like growth factor; men; quantitative ultrasound