title: [A twin study in Qingdao and Lishui: heritability of exercise participation and sedentary behavior].
abstract: OBJECTIVE
  To investigate both genetic and environmental influences on the exercise participation and sedentary behavior in Qingdao, Shandong province and 326 in Lishui, Zhejiang province.
  
  
  METHODS
  568 twin pairs, including 242 in Qingdao and 326 in Lishui, were studied. Exercise participation was measured by two questions on the frequency and intensity and then divided into two groups. Sedentary behavior was measured by one question as 'how long do you spend on sitting every day'. Variance component models based on twins was used to estimate the genetic and environmental factors on these traits.
  
  
  RESULTS
  The average age in monozygotic twins was (41.14 ± 10.11)while in dizygotic twins it was (41.23 ± 9.89). Genetic factors accounted 78% (35%-96%) and 59% (0-94%) for exercise participation variance in Qingdao and Lishui in people aged between 20 and 40. However, there were no heritability noticed on physical activity in people older than 40 years of age. Rates of heritability on sedentary behavior in Qingdao and Lishui were 68% (59%-75%) and 32% (7%-62%), respectively.
  
  
  CONCLUSIONS
  Results from the study suggested that sedentary behavior in Chinese people was influenced by genetic factors, which could also explain much of the exercise participation variance in people aged between 20 and 40.
authors.affiliation: Department of Epidemiology and Biostatistics, Public Health School, Peking University Health Science Center, Beijing 100191, China.
authors.forename: Feng
authors.initials: F
authors.lastname: Zhang
authors.affiliation: Department of Epidemiology and Biostatistics, Public Health School, Peking University Health Science Center, Beijing 100191, China.
authors.forename: Wenjing
authors.initials: W
authors.lastname: Gao
authors.affiliation: Department of Epidemiology and Biostatistics, Public Health School, Peking University Health Science Center, Beijing 100191, China.
authors.forename: Canqing
authors.initials: C
authors.lastname: Yu
authors.affiliation: Department of Epidemiology and Biostatistics, Public Health School, Peking University Health Science Center, Beijing 100191, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Lyu
authors.affiliation: Department of Epidemiology and Biostatistics, Public Health School, Peking University Health Science Center, Beijing 100191, China.
authors.forename: Shengfeng
authors.initials: S
authors.lastname: Wang
authors.affiliation: Department of Epidemiology and Biostatistics, Public Health School, Peking University Health Science Center, Beijing 100191, China.
authors.forename: Siyan
authors.initials: S
authors.lastname: Zhan
authors.affiliation: Department of Epidemiology and Biostatistics, Public Health School, Peking University Health Science Center, Beijing 100191, China.
authors.forename: Yonghua
authors.initials: Y
authors.lastname: Hu
authors.affiliation: Qingdao Center for Disease Control and Prevention.
authors.forename: Zengchang
authors.initials: Z
authors.lastname: Pang
authors.affiliation: Lishui Center for Disease Control and Prevention.
authors.forename: Weijian
authors.initials: W
authors.lastname: Chen
authors.affiliation: Qingdao Center for Disease Control and Prevention.
authors.forename: Shaojie
authors.initials: S
authors.lastname: Wang
authors.affiliation: Lishui Center for Disease Control and Prevention.
authors.forename: Rongfu
authors.initials: R
authors.lastname: Chen
authors.affiliation: Department of Epidemiology and Biostatistics, Public Health School, Peking University Health Science Center, Beijing 100191, China. Email: caoweihua60@163.com.
authors.forename: Weihua
authors.initials: W
authors.lastname: Cao
authors.affiliation: Department of Epidemiology and Biostatistics, Public Health School, Peking University Health Science Center, Beijing 100191, China. Email: lmlee@vip.163.com.
authors.forename: Liming
authors.initials: L
authors.lastname: Li
mesh_terms: D000328:Adult; D002681:China; D003430:Cross-Sectional Studies; D015444:Exercise; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D057185:Sedentary Behavior; D011795:Surveys and Questionnaires; D014427:Twins / Q000235:genetics*; D055815:Young Adult