title: Procollagen type 1 amino-terminal propeptide (P1NP) and risk of hip fractures in elderly Norwegian men and women. A NOREPOS study.
abstract: The current study aimed to assess a possible association between the bone turnover marker procollagen type 1 amino-terminal propeptide (P1NP) and future hip fractures in elderly Norwegian men and women and to elucidate the relation between P1NP, bone mineral density and 25-hydroxyvitamin D (25(OH)D). Men and women aged 71 to 77 from two population based health studies in Norway (1999-2001) were followed for a median period of 7.3 years with respect to hip fractures. The study was designed as a case-cohort study. P1NP and 25(OH)D were analysed in frozen serum samples obtained at baseline in hip fracture patients (n=340) and in randomly selected sex stratified sub-cohorts. Bone mineral density was measured by dual-energy X-ray absorptiometry (DXA) in a subset of participants. Cox proportional hazards regression with inverse probability weighting and robust variance was performed. No significant correlation between 25(OH)D and P1NP was found. A negative correlation between P1NP and BMD was observed in women (Rho=-0.36, p=0.001). A similar trend was observed in men. No association between quartiles of P1NP and rate of subsequent hip fractures was found. Spline analyses suggested a higher rate of hip fracture at P1NP levels above 60 μg/L in both men and women. A higher hip fracture rate, which was independent of BMD, was also indicated in women with very low levels of P1NP.
authors.affiliation: Department of Internal Medicine, Innlandet Hospital Trust, Hamar, Norway; Faculty of Medicine, University of Oslo, Oslo, Norway. Electronic address: trine.finnes@sykehuset-innlandet.no.
authors.forename: T E
authors.initials: TE
authors.lastname: Finnes
authors.affiliation: Department of Endocrinology, Oslo University Hospital, Oslo, Norway.
authors.forename: C M
authors.initials: CM
authors.lastname: Lofthus
authors.affiliation: Faculty of Medicine, University of Oslo, Oslo, Norway; Division of Epidemiology, Norwegian Institute of Public Health, Oslo, Norway.
authors.forename: H E
authors.initials: HE
authors.lastname: Meyer
authors.affiliation: Department of Endocrinology, Oslo University Hospital, Oslo, Norway.
authors.forename: E F
authors.initials: EF
authors.lastname: Eriksen
authors.affiliation: Department of Global Public Health and Primary Care, University of Bergen, Bergen, Norway; Department of Rheumatology, Haukeland University Hospital, Bergen, Norway.
authors.forename: E M
authors.initials: EM
authors.lastname: Apalset
authors.affiliation: Department of Global Public Health and Primary Care, University of Bergen, Bergen, Norway.
authors.forename: G S
authors.initials: GS
authors.lastname: Tell
authors.affiliation: Hormone Laboratory, Oslo University Hospital, Oslo, Norway.
authors.forename: P
authors.initials: P
authors.lastname: Torjesen
authors.affiliation: Division of Epidemiology, Norwegian Institute of Public Health, Oslo, Norway.
authors.forename: S O
authors.initials: SO
authors.lastname: Samuelsen
authors.affiliation: Division of Epidemiology, Norwegian Institute of Public Health, Oslo, Norway.
authors.forename: K
authors.initials: K
authors.lastname: Holvik
mesh_terms: D000368:Aged; D015331:Cohort Studies; D005260:Female; D006620:Hip Fractures / Q000097:blood / Q000453:epidemiology*; D006801:Humans; D008297:Male; D009664:Norway / Q000453:epidemiology; D010446:Peptide Fragments / Q000097:blood*; D011347:Procollagen / Q000097:blood*; D016016:Proportional Hazards Models; D012307:Risk Factors
chemical_list: D010446:Peptide Fragments; D011347:Procollagen; C047202:procollagen Type I N-terminal peptide
keywords: Bone turnover marker; Elderly; Hip fractures; Osteoporosis; Procollagen type 1 amino-terminal propeptide