title: Clinical subsequent fractures cluster in time after first fractures.
abstract: OBJECTIVE
  The risk of subsequent fractures is double the risk of having a first fracture. We analysed whether this risk is constant or not over time.
  
  
  METHODS
  A population-based study in 4140 postmenopausal women, aged between 50 and 90 years, on radiographic confirmed clinical fractures from menopause onwards analysed by Cox regression.
  
  
  RESULTS
  A total of 924 (22%) women had a first fracture and 243 (26% of 924) a subsequent fracture. Of all first fractures, 4% occurred in each year from menopause onwards, while after a first fracture 23% of all subsequent fractures occurred within 1 year and 54% within 5 years. When calculated from time of first fracture, the relative risk (RR) of subsequent fracture was 2.1 (95% CI 1.7 to 2.6) and remained increased over 15 years. When calculated for specific time intervals after a first fracture, the RR was 5.3 (95% CI 4.0 to 6.6) within 1 year, 2.8 (95% CI 2.0 to 3.6) within 2-5 years, 1.4 (95% CI 1.0 to 1.8) within 6-10 years and 0.41 (95% CI 0.29 to 0.53) after >10 years.
  
  
  CONCLUSIONS
  From menopause onwards, clinical fractures cluster in time, indicating the need for early action to prevent subsequent fractures.
authors.affiliation: Maastricht University, Department of General Practice, PO Box 616, 6200 MD, Maastricht, The Netherlands. t.vangeel@hag.unimaas.nl
authors.forename: T A C M
authors.initials: TA
authors.lastname: van Geel
authors.forename: S
authors.initials: S
authors.lastname: van Helden
authors.forename: P P
authors.initials: PP
authors.lastname: Geusens
authors.forename: B
authors.initials: B
authors.lastname: Winkens
authors.forename: G-J
authors.initials: GJ
authors.lastname: Dinant
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D016000:Cluster Analysis; D016001:Confidence Intervals; D003430:Cross-Sectional Studies; D005260:Female; D050723:Fractures, Bone / Q000209:etiology*; D006801:Humans; D008875:Middle Aged; D017698:Postmenopause / Q000502:physiology*; D016016:Proportional Hazards Models; D012306:Risk; D013997:Time Factors