{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,6]],"date-time":"2026-03-06T00:29:53Z","timestamp":1772756993844,"version":"3.50.1"},"reference-count":34,"publisher":"BMJ","issue":"1","content-domain":{"domain":["bmj.com"],"crossmark-restriction":true},"short-container-title":["BMJ Open"],"accepted":{"date-parts":[[2013,11,20]]},"published-print":{"date-parts":[[2014,1]]},"abstract":"<jats:sec>\n                    <jats:title>Objectives<\/jats:title>\n                    <jats:p>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.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Design<\/jats:title>\n                    <jats:p>Prospective cohort study.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Setting<\/jats:title>\n                    <jats:p>10 public schools in the municipality of Svendborg, Denmark.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Participants<\/jats:title>\n                    <jats:p>A total of 1259 school children aged 6\u201312\u2005years participating in the Childhood Health, Activity, and Motor Performance School Study Denmark.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>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.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>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.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusions<\/jats:title>\n                    <jats:p>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.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1136\/bmjopen-2013-004165","type":"journal-article","created":{"date-parts":[[2014,1,9]],"date-time":"2014-01-09T01:03:26Z","timestamp":1389229406000},"page":"e004165","update-policy":"https:\/\/doi.org\/10.1136\/crossmarkpolicy","source":"Crossref","is-referenced-by-count":17,"title":["Seasonal variation in musculoskeletal extremity injuries in school children aged 6\u201312 followed prospectively over 2.5\u2005years: a cohort study"],"prefix":"10.1136","volume":"4","author":[{"given":"Eva","family":"Jespersen","sequence":"first","affiliation":[{"name":"Centre of Research in Childhood Health, Institute of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Ren\u00e9","family":"Holst","sequence":"additional","affiliation":[{"name":"Department of Biostatistics, Institute of Regional Health Research, University of Southern Denmark, Odense, Denmark"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Claudia","family":"Franz","sequence":"additional","affiliation":[{"name":"Centre of Research in Childhood Health, Institute of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Christina T","family":"Rexen","sequence":"additional","affiliation":[{"name":"Centre of Research in Childhood Health, Institute of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Niels","family":"Wedderkopp","sequence":"additional","affiliation":[{"name":"Centre of Research in Childhood Health, Institute of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark"},{"name":"The Sport Medicine Clinic, Orthopaedic Department, Hospital of Lillebaelt, and Institute of Regional Health Service Research, University of Southern Denmark, Odense, Denmark"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"239","published-online":{"date-parts":[[2014,1,8]]},"reference":[{"key":"2025120521053738000_4.1.e004165.1","doi-asserted-by":"publisher","DOI":"10.1016\/S0304-3959(97)00073-0"},{"key":"2025120521053738000_4.1.e004165.2","doi-asserted-by":"publisher","DOI":"10.1016\/j.pain.2004.03.021"},{"key":"2025120521053738000_4.1.e004165.3","doi-asserted-by":"publisher","DOI":"10.1097\/01241398-200309000-00010"},{"key":"2025120521053738000_4.1.e004165.4","doi-asserted-by":"publisher","DOI":"10.1136\/ip.9.2.117"},{"key":"2025120521053738000_4.1.e004165.5","doi-asserted-by":"publisher","DOI":"10.1136\/bjsm.32.3.220"},{"key":"2025120521053738000_4.1.e004165.6","doi-asserted-by":"publisher","DOI":"10.1139\/H07-182"},{"key":"2025120521053738000_4.1.e004165.7","doi-asserted-by":"publisher","DOI":"10.1136\/bjsm.2010.082545"},{"key":"2025120521053738000_4.1.e004165.8","doi-asserted-by":"publisher","DOI":"10.2165\/00007256-200333120-00001"},{"key":"2025120521053738000_4.1.e004165.9","doi-asserted-by":"publisher","DOI":"10.1136\/bjsm.37.4.354"},{"key":"2025120521053738000_4.1.e004165.10","doi-asserted-by":"publisher","DOI":"10.1177\/0363546510373876"},{"key":"2025120521053738000_4.1.e004165.11","doi-asserted-by":"publisher","DOI":"10.1177\/036354658901700214"},{"key":"2025120521053738000_4.1.e004165.12","doi-asserted-by":"crossref","first-page":"281","DOI":"10.1111\/j.1600-0838.1996.tb00471.x","article-title":"The epidemiology of sports injuries in school-aged children","volume":"6","author":"Sorensen","year":"1996","journal-title":"Scand J Med Sci Sports"},{"key":"2025120521053738000_4.1.e004165.13","doi-asserted-by":"publisher","DOI":"10.1136\/bjsm.2008.055483"},{"key":"2025120521053738000_4.1.e004165.14","doi-asserted-by":"crossref","unstructured":"Jespersen E Holst R Franz C . 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