title: Associations between aspects of friendship networks, physical activity, and sedentary behaviour among adolescents.
abstract: BACKGROUND
  Adolescent friendships have been linked to physical activity levels; however, network characteristics have not been broadly examined.
  
  
  METHODS
  In a cross-sectional analysis of 1061 adolescents (11-15 years), achieving 60 minutes/day of moderate-to-vigorous physical activity (MVPA) and participating in over 2 hours/day of sedentary behaviour were determined based on friendship network characteristics (density; proportion of active/sedentary friends; betweenness centrality; popularity; clique membership) and perceived social support.
  
  
  RESULTS
  Adolescents with no friendship nominations participated in less MVPA. For boys and girls, a ten percent point increase in active friends was positively associated with achievement of 60 minutes/day of MVPA (OR 1.11; 95% CI 1.02-1.21, OR 1.14; 95% CI 1.02-1.27, resp.). For boys, higher social support from friends was negatively associated with achieving 60 minutes/day of MVPA (OR 0.63; 95% CI 0.42-0.96). Compared with low density networks, boys in higher density networks were more likely to participate in over 2 hours/day of sedentary behaviour (OR 2.93; 95% CI 1.32-6.49). Social support from friends also modified associations between network characteristics and MVPA and sedentary behaviour.
  
  
  CONCLUSIONS
  Different network characteristics appeared to have different consequences. The proportion of active close friends was associated with MVPA, while network density was associated with sedentary behaviour. This poses challenges for intervention design.
authors.affiliation: University of Calgary, Teaching Research and Wellness Building, 3rd Floor, 3280 Hospital, Drive NW, AB, Canada T2N 4Z6.
authors.forename: Keri Jo
authors.identifier: 0000-0003-3022-7903
authors.initials: KJ
authors.lastname: Sawka
authors.affiliation: University of Calgary, Teaching Research and Wellness Building, 3rd Floor, 3280 Hospital, Drive NW, AB, Canada T2N 4Z6.
authors.forename: Gavin R
authors.initials: GR
authors.lastname: McCormack
authors.affiliation: Alberta Children's Hospital, Room C4-435, 2888 Shaganappi, Trail NW, Calgary, AB, Canada T3B 6A8.
authors.forename: Alberto
authors.initials: A
authors.lastname: Nettel-Aguirre
authors.affiliation: University of Calgary, Teaching Research and Wellness Building, 3rd Floor, 3280 Hospital, Drive NW, AB, Canada T2N 4Z6.
authors.forename: Anita
authors.initials: A
authors.lastname: Blackstaffe
authors.affiliation: University of Calgary, Teaching Research and Wellness Building, 3rd Floor, 3280 Hospital, Drive NW, AB, Canada T2N 4Z6.
authors.forename: Rosemary
authors.initials: R
authors.lastname: Perry
authors.affiliation: University of Calgary, Teaching Research and Wellness Building, 3rd Floor, 3280 Hospital, Drive NW, AB, Canada T2N 4Z6.
authors.forename: Penelope
authors.initials: P
authors.lastname: Hawe
mesh_terms: D000293:Adolescent; D000294:Adolescent Behavior / Q000523:psychology*; D002648:Child; D003430:Cross-Sectional Studies; D015444:Exercise; D005260:Female; D033062:Friends / Q000523:psychology*; D015438:Health Behavior; D006801:Humans; D007899:Leisure Activities; D008297:Male; D012572:School Health Services; D012574:Schools; D057185:Sedentary Behavior; D012944:Social Support; D012959:Socioeconomic Factors