title: Forearm fractures in Central Norway, 1999-2012: incidence, time trends, and seasonal variation.
abstract: The incidence of forearm fractures for men and women ≥40 years in Central Norway was high during the period 1999-2012. A decline in fractures was observed only among women over 50 years. A seasonal variation with highest incidence in the winter months was found among women.
  
  
  OBJECTIVE
  The aim of this study was to examine the incidence of forearm fractures in Central Norway in men and women 40 years and older from 1999 to 2012 and assess time trends as well as seasonal variations.
  
  
  METHODS
  Data is from the fracture registry in Nord-Trøndelag, including all forearm fractures in persons ≥40 sustained from 1999 to 2012. Annual incidence of forearm fractures were calculated and tested for trends. Variations in the occurrence of fractures were explored by comparing proportion of fractures by month and seasons.
  
  
  RESULTS
  The study population consisted of 4003 subjects (77.1% women). The total number of fractures were 4240. There was an increase in fractures for women with increasing age, steepest, a three-fold increase between age group 40-50 and the age group 50-60. Among men, this pattern was not observed as incidences did not change with increasing age. The age-standardized incidence rate for all fractures among women ≥50 ranged from 82 fractures per 1000 (95% CI 71-94) to 100 (88-114) and among men from 19 (14-27) to 31 (24-39). Restricting the analysis to the first fracture sustained during the observed period, women ≥50 years showed a reduction in fractures of 1.30% per year (95% CI 0.01%: 2.56%,) and 12.18% per 10 years (3.61%: 19.98%). For all women, there was a trend towards a decline of 0.73% per year (-2.29%: 0.85%), although not significant. For men, there was a trend towards an increase in fractures of 1.66% per year (-0.11%: 3.45%). The occurrence of fractures among women varied by season of the year, with higher fracture rates in the winter months.
  
  
  CONCLUSIONS
  The incidence rate of forearm fractures in Central Norway was high. However, a small decline in the incidence of the first fracture among women older than 50 years was observed. Fractures were more often sustained during winter months among women.
authors.affiliation: Department of Public Health and General Practice, Norwegian University of Science and Technology, PB 8905, 7491, Trondheim, Norway. mari.hoff@ntnu.no.|Department of Rheumatology, St Olavs Hospital, Trondheim, Norway. mari.hoff@ntnu.no.
authors.forename: Mari
authors.initials: M
authors.lastname: Hoff
authors.affiliation: Faculty of Medicine, Norwegian University of Science and Technology, Trondheim, Norway.
authors.forename: Ingrid Ask
authors.initials: IA
authors.lastname: Torvik
authors.affiliation: Department of Public Health and General Practice, Norwegian University of Science and Technology, PB 8905, 7491, Trondheim, Norway.|Department of Gynecology, St Olavs Hospital, Trondheim, Norway.
authors.forename: Berit
authors.initials: B
authors.lastname: Schei
mesh_terms: D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D005543:Forearm Injuries / Q000453:epidemiology*; D050723:Fractures, Bone / Q000453:epidemiology*; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009664:Norway / Q000453:epidemiology; D012042:Registries; D012621:Seasons; D017678:Sex Distribution; D013997:Time Factors
keywords: Forearm fracture; Osteoporosis; Seasonal variation; Time trends