title: Cross-sectional associations of objectively measured physical activity with brain-derived neurotrophic factor in adolescents.
abstract: The purpose of this study was to examine the associations between objectively measured physical activity and serum brain-derived neurotrophic factor (BDNF) in adolescents.
  
  
  
  Cross-sectional analyses were performed using data from 415 adolescents who participated in the 2015 follow-up of the Childhood Health Activity and Motor Performance School Study Denmark (the CHAMPS-study DK). Physical activity was objectively measured by accelerometry monitors. Serum BDNF levels were analyzed using the Enzyme-linked immunosorbent assay (ELISA). Anthropometrics and pubertal status were measured using standardized procedures.
  
  
  
  With adjustment for age, pubertal status and body mass index, mean physical activity (counts per minute) was negatively associated with serum BDNF in boys (P=0.013). Similarly, moderate-to-vigorous physical activity (MVPA) was negatively associated with serum BDNF in boys (P=0.035). In girls, mean physical activity and MVPA were not associated with serum BDNF. Without adjustment for wear time, sedentary time was not associated with serum BDNF in either sex.
  
  
  
  These findings indicate that higher physical activity is associated with lower serum BDNF in boys, but not in girls.
authors.affiliation: Department of Physical Education, Shanghai Jiao Tong University, Shanghai, China.
authors.forename: Tao
authors.initials: T
authors.lastname: Huang
authors.affiliation: Centre of Research in Childhood Health, Department of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark.
authors.forename: Anne Kær
authors.initials: AK
authors.lastname: Gejl
authors.affiliation: Centre of Research in Childhood Health, Department of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark.
authors.forename: Jakob
authors.initials: J
authors.lastname: Tarp
authors.affiliation: Faculty of Teacher Education and Sport, Sogn og Fjordane University College, Sogndal, Norway; Department of Sports Medicine, Norwegian School of Sport Sciences, Oslo, Norway.
authors.forename: Lars Bo
authors.initials: LB
authors.lastname: Andersen
authors.affiliation: The Centre of Inflammation and Metabolism and the Centre for Physical Activity Research, Department of Infectious Diseases, Rigshospitalet, University of Copenhagen, Denmark.
authors.forename: Lone
authors.initials: L
authors.lastname: Peijs
authors.affiliation: Centre of Research in Childhood Health, Department of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark. Electronic address: anbugge@health.sdu.dk.
authors.forename: Anna
authors.initials: A
authors.lastname: Bugge
mesh_terms: D061725:Accelerometry; D000293:Adolescent; D000886:Anthropometry; D019208:Brain-Derived Neurotrophic Factor / Q000097:blood*; D003430:Cross-Sectional Studies; D004797:Enzyme-Linked Immunosorbent Assay; D015444:Exercise / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D009043:Motor Activity; D057185:Sedentary Behavior; D012741:Sexual Maturation / Q000502:physiology
chemical_list: D019208:Brain-Derived Neurotrophic Factor; C579455:BDNF protein, human
keywords: Adolescents; Brain-derived neurotrophic factor; Moderate to vigorous physical activity; Physical activity