title: Family influences on physical activity and sedentary behaviours in Chinese junior high school students: a cross-sectional study.
abstract: BACKGROUND
  Family influence plays an important role in a child's physical activity (PA). This study aimed to describe the level of moderate to vigorous intensity physical activity (MVPA) and sedentary behaviours among Chinese junior high school students and examine the associations between different types of family influence and MVPA or sedentary behaviours.
  
  
  METHODS
  Participants of two independent cross-sectional surveys, conducted in 2009 and 2011, were students in Grade 7 and 9 from all junior high schools in Hangzhou, China. The daily duration and frequency of MVPA, amount of sedentary time and frequency of family support were self-reported. Multi-level mixed-effects logistic regression was used to examine the associations between different types or levels of family influence and MVPA or sedentary behaviours.
  
  
  RESULTS
  A total of 7286 students were analysed finally. Overall, only 9.0% of the students participated in MVPA at least 60 minutes/day; 63.9% spent no more than 2 hours/day in sedentary behaviours. Frequent verbal encouragement and watching were associated with less leisure-time sedentary behaviours. The multivariate-adjusted odds ratios (ORs) for verbal encouragement and watching were 1.29 (95% CI, 1.08 to 1.55) and 1.19 (95% CI, 0.97 to 1.45) for 5-7 days per week. The involvement of family in the children's activity in most days of the week was associated with both higher level of MVPA and less leisure-time sedentary behaviours. The respective ORs among students who reported familial support 5-7 days per week, were 1.50 (95% CI, 1.21 to 1.86) for engaging in seven days of MVPA per week, 1.67 (95% CI, 1.19 to 2.32) for at least 60 minutes of MVPA daily, and 1.48 (95% CI, 1.19 to 1.84) for no more than 2 hours of leisure-time sedentary behaviours daily.
  
  
  CONCLUSIONS
  This study found that less than 10.0% of urban Chinese adolescents engaged in MVPA at least 60 minutes/day. Family involving themselves in the children's activity exerted the most significant influence on children's behaviours as compared with verbally encouraging and observing children's activity. Any type of familial support including verbally encouraging, watching, and involving had effects on reducing leisure-time sedentary behaviours.
authors.affiliation: Department of Epidemiology and Biostatistics, School of Public Health, Peking University Health Science Centre, Beijing, 100191, China. wang1156841625@126.com.
authors.forename: Xin
authors.initials: X
authors.lastname: Wang
authors.affiliation: Division for Chronic and Non-Communicable Disease Control and Prevention, Hangzhou Centre for Disease Control and Prevention, Mingshi Road, Jianqiao Town, Hangzhou, 310021, China. liuqingmin64@sohu.com.
authors.forename: Qing-Min
authors.initials: QM
authors.lastname: Liu
authors.affiliation: Division for Chronic and Non-Communicable Disease Control and Prevention, Hangzhou Centre for Disease Control and Prevention, Mingshi Road, Jianqiao Town, Hangzhou, 310021, China. yanjunren_hz@aliyun.com.
authors.forename: Yan-Jun
authors.initials: YJ
authors.lastname: Ren
authors.affiliation: Department of Epidemiology and Biostatistics, School of Public Health, Peking University Health Science Centre, Beijing, 100191, China. lvjun@bjmu.edu.cn.
authors.forename: Jun
authors.initials: J
authors.lastname: Lv
authors.affiliation: Department of Epidemiology and Biostatistics, School of Public Health, Peking University Health Science Centre, Beijing, 100191, China. lmlee@vip.163.com.
authors.forename: Li-Ming
authors.initials: LM
authors.lastname: Li
mesh_terms: D000293:Adolescent; D000367:Age Factors; D044466:Asian People; D002648:Child; D002681:China; D003430:Cross-Sectional Studies; D015444:Exercise; D005190:Family; D005260:Female; D015438:Health Behavior; D006801:Humans; D007899:Leisure Activities; D016015:Logistic Models; D008297:Male; D016017:Odds Ratio; D057185:Sedentary Behavior; D057566:Self Report; D012737:Sex Factors; D012959:Socioeconomic Factors; D014505:Urban Population