title: Body mass index is associated with low back pain in childhood and adolescence: a birth cohort study with a 6-year follow-up in Niigata City, Japan.
abstract: OBJECTIVE
  To investigate the successive change of low back pain (LBP) prevalence in childhood and adolescence and to examine the associations between LBP and extracurricular sports activities (ECSA) or body mass index (BMI) using a 6-year birth cohort study.
  
  
  METHODS
  LBP reports of a grade (4,597 pupils at the beginning) were tracked over 6 years (between the ages of 9 and 14 years old), and anonymous questionnaires were distributed to them yearly. After grading the severity of the LBP into three levels and noting the transitions of the point and the lifetime prevalence of LBP, associations between point prevalence of LBP and BMI or ECSA were evaluated.
  
  
  RESULTS
  The point prevalence of LBP had a tendency to become significantly higher as the pupils got older until they became 13 years old. The lifetime prevalence of LBP significantly increased as they got older yearly. As for the severity of LBP among students with a lifetime prevalence, the rate of more severe LBP (levels 2 and 3) increased as they got older. Significant positive associations were recognized between BMI and point prevalence of LBP in every years old (p < 0.05) and between ECSA and point prevalence of LBP at 11 (p = 0.001) and 14 years old (p < 0.001).
  
  
  CONCLUSIONS
  The point and lifetime prevalence of LBP and the rate of more severe LBP increased as the pupils got older. BMI may be associated with LBP in childhood and adolescence.
authors.affiliation: Department of Orthopaedic Surgery, Niigata University Medical and Dental General Hospital, 1-757 Asahimachidori, Chuoku, Niigata City, Niigata, 951-8510, Japan, cbe90900@pop06.odn.ne.jp.
authors.forename: Atsuki
authors.initials: A
authors.lastname: Sano
authors.forename: Toru
authors.initials: T
authors.lastname: Hirano
authors.forename: Kei
authors.initials: K
authors.lastname: Watanabe
authors.forename: Naoto
authors.initials: N
authors.lastname: Endo
authors.forename: Takui
authors.initials: T
authors.lastname: Ito
authors.forename: Naohito
authors.initials: N
authors.lastname: Tanabe
mesh_terms: D000293:Adolescent; D015992:Body Mass Index; D002648:Child; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007564:Japan / Q000453:epidemiology; D017116:Low Back Pain / Q000453:epidemiology / Q000209:etiology*; D008297:Male; D050177:Overweight / Q000150:complications*; D015995:Prevalence; D012307:Risk Factors; D012720:Severity of Illness Index; D013177:Sports / Q000706:statistics & numerical data; D011795:Surveys and Questionnaires