title: Seasonal variation in musculoskeletal extremity injuries in school children aged 6-12 followed prospectively over 2.5 years: a cohort study.
abstract: OBJECTIVE
  The type and level of physical activity in children vary over seasons and might thus influence the injury patterns. However, very little information is available on the distribution of injuries over the calendar year. This study aims to describe and analyse the seasonal variation in extremity injuries in children.
  
  
  METHODS
  Prospective cohort study.
  
  
  METHODS
  10 public schools in the municipality of Svendborg, Denmark.
  
  
  METHODS
  A total of 1259 school children aged 6-12 years participating in the Childhood Health, Activity, and Motor Performance School Study Denmark.
  
  
  METHODS
  School children were surveyed each week during 2.5 school-years. Musculoskeletal injuries were reported by parents answering automated mobile phone text questions (SMS-Track) on a weekly basis and diagnosed by clinicians. Data were analysed for prevalence and incidence rates over time with adjustments for gender and age.
  
  
  RESULTS
  Injuries in the lower extremities were reported most frequently (n=1049). There was a significant seasonal variation in incidence and prevalence for lower extremity injuries and for lower and upper extremity injuries combined (n=1229). For the upper extremities (n=180), seasonal variation had a significant effect on the risk of prevalence. Analysis showed a 46% increase in injury incidence and a 32% increase in injury prevalence during summer relative to winter for lower and upper extremity injuries combined.
  
  
  CONCLUSIONS
  There are clear seasonal differences in the occurrence of musculoskeletal extremity injuries among children with almost twice as high injury incidence and prevalence estimates during autumn, summer and spring compared with winter. This suggests further research into the underlying causes for seasonal variation and calls for preventive strategies to be implemented in order to actively prepare and supervise children before and during high-risk periods.
authors.affiliation: Centre of Research in Childhood Health, Institute of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark.
authors.forename: Eva
authors.initials: E
authors.lastname: Jespersen
authors.forename: René
authors.initials: R
authors.lastname: Holst
authors.forename: Claudia
authors.initials: C
authors.lastname: Franz
authors.forename: Christina T
authors.initials: CT
authors.lastname: Rexen
authors.forename: Niels
authors.initials: N
authors.lastname: Wedderkopp
mesh_terms: D001134:Arm Injuries / Q000453:epidemiology*; D002648:Child; D015331:Cohort Studies; D005260:Female; D006801:Humans; D015994:Incidence; D007869:Leg Injuries / Q000453:epidemiology*; D008297:Male; D009141:Musculoskeletal System / Q000293:injuries*; D015995:Prevalence; D011446:Prospective Studies; D012621:Seasons; D013997:Time Factors
keywords: Public Health; Sports Medicine