title: Insulin-like growth factor I and risk of incident cancer in elderly men - results from MrOS (Osteoporotic Fractures in Men) in Sweden.
abstract: OBJECTIVE
  Studies of the association between circulating IGF-I and cancer risk have shown conflicting results. We have previously observed a U-shaped association between IGF-I and cancer mortality. This study test the hypotheses of a U-shaped association between IGF-I and incident cancer.
  
  
  METHODS
  Elderly men (2368), randomly recruited from the general community.
  
  
  METHODS
  IGF-I was measured in a cohort of elderly men. Complete data for incident cancer were obtained from the Swedish Cancer Registry. Statistical analyses included Cox proportional hazards regressions with or without a spline approach.
  
  
  RESULTS
  Three hundred and sixty-nine participants had incident cancer after baseline. Prostate cancer was most frequent (n = 140). There was no association between serum IGF-I and all cancer or prostate cancer incidence. However, there was a nonlinear association between IGF-I and nonprostate cancer incidence (P = <0·05). Exploratory analyses were performed for low and high serum IGF-I (quintiles 1 and 5) vs intermediate (quintiles 2-4, referent). There was a tendency of increased nonprostate cancer risk in men with high IGF-I (HR = 1·26, 95% confidence interval (CI): 0·92-1·71, P = 0·15). After excluding participants with follow-up of less than 2·6 years (half median follow-up time), to control for potential diagnostic delay, the association was statistically significant (HR = 1·55, CI: 1·03-2·35).
  
  
  CONCLUSIONS
  There was a significant nonlinear association between IGF-I and nonprostate cancer. No association between IGF-I and prostate cancer was observed. Future studies are warranted to further investigate this nonlinear association, including whether IGF-I concentration is a reproducible, and useful, risk marker of nonprostate cancer.
authors.affiliation: Center for Bone and Arthritis Research at the Sahlgrenska Academy (CBAR), Institute of Medicine, University of Gothenburg, Gothenburg, Sweden.
authors.forename: Daniel
authors.initials: D
authors.lastname: Carlzon
authors.affiliation: Center for Bone and Arthritis Research at the Sahlgrenska Academy (CBAR), Institute of Medicine, University of Gothenburg, Gothenburg, Sweden.
authors.forename: Johan
authors.initials: J
authors.lastname: Svensson
authors.affiliation: Center for Applied Biostatistics at the Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
authors.forename: Max
authors.initials: M
authors.lastname: Petzold
authors.affiliation: Clinical and Molecular Osteoporosis Research Unit, Department of Orthopaedics and Clinical Sciences, Lund University, Skåne University Hospital, Malmö, Sweden.
authors.forename: Magnus K
authors.initials: MK
authors.lastname: Karlsson
authors.affiliation: Department of Medical Sciences, University of Uppsala, Uppsala, Sweden.
authors.forename: Östen
authors.initials: Ö
authors.lastname: Ljunggren
authors.affiliation: Department of Urology, Institute of Clinical Sciences, University of Gothenburg, Gothenburg, Sweden.
authors.forename: Mohammad-Ali
authors.initials: MA
authors.lastname: Haghsheno
authors.affiliation: Department of Urology, Institute of Clinical Sciences, University of Gothenburg, Gothenburg, Sweden.
authors.forename: Jan-Erik
authors.initials: JE
authors.lastname: Damber
authors.affiliation: Center for Bone and Arthritis Research at the Sahlgrenska Academy (CBAR), Institute of Medicine, University of Gothenburg, Gothenburg, Sweden.
authors.forename: Dan
authors.initials: D
authors.lastname: Mellström
authors.affiliation: Center for Bone and Arthritis Research at the Sahlgrenska Academy (CBAR), Institute of Medicine, University of Gothenburg, Gothenburg, Sweden.
authors.forename: Claes
authors.initials: C
authors.lastname: Ohlsson
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D006801:Humans; D015994:Incidence; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D008297:Male; D009369:Neoplasms / Q000097:blood* / Q000453:epidemiology*; D058866:Osteoporotic Fractures / Q000453:epidemiology; D016016:Proportional Hazards Models; D011471:Prostatic Neoplasms / Q000097:blood / Q000453:epidemiology; D012042:Registries / Q000706:statistics & numerical data; D018570:Risk Assessment / Q000379:methods / Q000706:statistics & numerical data*; D012307:Risk Factors; D011795:Surveys and Questionnaires; D013548:Sweden / Q000453:epidemiology
chemical_list: D007334:Insulin-Like Growth Factor I