Procollagen type 1 amino-terminal propeptide (P1NP) and risk of hip fractures in elderly Norwegian men and women. A NOREPOS study

• Published in: Bone (New York, N.Y.) N.Y.), 2014-07, Vol.64, p.1-7
• Main Authors: Finnes, T.E, Lofthus, C.M, Meyer, H.E, Eriksen, E.F, Apalset, E.M, Tell, G.S, Torjesen, P, Samuelsen, S.O, Holvik, K
• Format: Article
• Language: English
• Subjects: Aged; Biological and medical sciences; Bone turnover marker; Cohort Studies; Elderly; Female; Fundamental and applied biological sciences. Psychology; Hip fractures; Hip Fractures - blood; Hip Fractures - epidemiology; Humans; Injuries of the limb. Injuries of the spine; Male; Medical sciences; Norway - epidemiology; Orthopedics; Osteoporosis; Peptide Fragments - blood; Procollagen - blood; Procollagen type 1 amino-terminal propeptide; Proportional Hazards Models; Risk Factors; Skeleton and joints; Traumas. Diseases due to physical agents; Vertebrates: anatomy and physiology, studies on body, several organs or systems; Vertebrates: osteoarticular system, musculoskeletal system
• ISSN: 8756-3282; 1873-2763
• DOI: 10.1016/j.bone.2014.03.010

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.