title: Influence of physical activity on vertebral strength during late adolescence.
abstract: BACKGROUND
  Reduced vertebral strength is a clear risk factor for vertebral fractures. Men and women with vertebral fractures often have reduced vertebral size and bone mineral density (BMD). Vertebral strength is controlled by both genetic and developmental factors. Malnutrition and low levels of physical activity are commonly considered to result in reduced bone size during growth. Several studies have also demonstrated the general relationship between BMD and physical activity in the appendicular skeleton.
  
  
  OBJECTIVE
  In this study, we wanted to clarify the role of physical activity on vertebral bodies. Vertebral dimensions appear to generally be less pliant than long bones when lifetime changes occur. We wanted to explore the association between physical activity during late adolescence and vertebral strength parameters such as cross-sectional size and BMD.
  
  
  METHODS
  The association between physical activity and vertebral strength was explored by measuring vertebral strength parameters and defining the level of physical activity during adolescence.
  
  
  METHODS
  The study population consisted of 6,928 males and females who, at 15 to 16 and 19 years of age, responded to a mailed questionnaire inquiring about their physical activity. A total of 558 individuals at the mean age of 21 years underwent magnetic resonance imaging (MRI) scans.
  
  
  METHODS
  We measured the dimensions of the fourth lumbar vertebra from the MRI scans of the Northern Finland Birth Cohort 1986 and performed T2* relaxation time mapping, reflective of BMD. Vertebral strength was based on these two parameters. We analyzed the association of physical activity on vertebral strength using the analysis of variance.
  
  
  CONCLUSIONS
  We observed no association between the level of physical activity during late adolescence and vertebral strength at 21 years.
authors: Department of Anatomy and Cell Biology, Institute of Biomedicine, University of Oulu, PO Box 5000, Oulu 90014, Finland. juho-antti.junno@oulu.fi
authors: Juho-Antti
authors: JA
authors: Junno
authors: Markus
authors: M
authors: Paananen
authors: Jaro
authors: J
authors: Karppinen
authors: Tuija
authors: T
authors: Tammelin
authors: Jaakko
authors: J
authors: Niinimäki
authors: Eveliina
authors: E
authors: Lammentausta
authors: Markku
authors: M
authors: Niskanen
authors: Miika T
authors: MT
authors: Nieminen
authors: Marjo-Riitta
authors: MR
authors: Järvelin
authors: Jani
authors: J
authors: Takatalo
authors: Osmo
authors: O
authors: Tervonen
authors: Juha
authors: J
authors: Tuukkanen
mesh_terms: D000293:Adolescent; D015519:Bone Density / Q000502:physiology*; D005260:Female; D006801:Humans; D008159:Lumbar Vertebrae / Q000033:anatomy & histology / Q000502:physiology*; D008279:Magnetic Resonance Imaging; D008297:Male; D009043:Motor Activity / Q000502:physiology*; D010808:Physical Examination; D055815:Young Adult