title: The association between resting heart rate and blood pressure among children and adolescents with different waist circumferences.
abstract: Resting heart rate (RHR) is an accessible index of sympathetic activity. The objective of this study was to assess the associations between blood pressure (BP) and RHR in children with different waist circumferences (WCs). The data of the Chinese National Survey on Students' Constitution and Health in 2010 were used. A total of 91,762 participates aged 9 to 18 years with complete records were included. RHR was categorised into quintile groups and WC was stratified into small (<-1.035), medium (≥-1.035 and <1.035) and large (≥1.035) groups respectively, after they were converted into age- and sex-specific z-score. Multivariate linear regression revealed that the association between RHR z-score and BP was similar before and after WC was adjusted for. With 1 standard deviation variation in RHR, BP changed from 2.22 (95 % confidence interval (CI): 1.51, 2.93) to 3.58 mmHg (95 % CI: 2.54, 4.62) in small WC group and 1.83 (95 % CI: 1.10, 2.56) to 4.23 mmHg (95 % CI: 3.38, 5.09) in large WC group respectively.
  
  
  CONCLUSIONS
  This study revealed that BP was positively associated with RHR among children with different WCs, which implied the positive association between sympathetic activity and BP in children regardless of the amount of abdominal fat.
authors.affiliation: Institute of Child and Adolescent Health, School of Public Health, Peking University Health Science Center, 38 Xueyuan Road, Haidian District, Beijing, 100191, People's Republic of China, b.dong@uq.edu.au.
authors.forename: Bin
authors.initials: B
authors.lastname: Dong
authors.forename: Zhiqiang
authors.initials: Z
authors.lastname: Wang
authors.forename: Hai-Jun
authors.initials: HJ
authors.lastname: Wang
authors.forename: Jun
authors.initials: J
authors.lastname: Ma
mesh_terms: D000293:Adolescent; D001794:Blood Pressure / Q000502:physiology*; D002648:Child; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D006973:Hypertension / Q000503:physiopathology; D016014:Linear Models; D008297:Male; D063766:Pediatric Obesity / Q000097:blood / Q000150:complications; D012189:Retrospective Studies; D013564:Sympathetic Nervous System / Q000378:metabolism / Q000502:physiology; D055105:Waist Circumference / Q000502:physiology*