title: Racial differences in the influence of body size on ambulatory blood pressure in youths.
abstract: BACKGROUND
  African Americans have higher night-time blood pressures than Caucasians do despite their having similar daytime blood pressures. It is well established that body size is related to casual blood pressure.
  
  
  OBJECTIVE
  To examine the influence of body size on racial differences in patterns of ambulatory blood pressure.
  
  
  METHODS
  Ambulatory blood pressure recordings were performed on 292 healthy children and adolescents (148 African Americans and 144 Caucasian) aged 10-18 years (mean 13+/-2 years). These blood pressures were related to height, weight, body surface area, and body mass index in separate regression models that also included race, sex, and age as factors.
  
  
  RESULTS
  The race-by-height interaction was significant for night-time systolic blood pressure (P<0.02), with a significant relationship for African Americans (P<0. 0001), but not for Caucasians. The race-by-weight interaction was significant for night-time systolic blood pressure (P<0.04), also with a greater relationship for African Americans (P<0.0001) than for Caucasians (P<0.03). In addition, the race-by-weight interaction was significant for night-time diastolic blood pressure (P<0.04), with a significant relationship for African Americans (P<0.01), but not for Caucasians. Finally, the race-by-body-surface-area interaction was significant for night-time diastolic blood pressure (P<0.05), again with a significant relationship for African Americans (P<0.02) but not for Caucasians.
  
  
  CONCLUSIONS
  Differences in the relationship between body size and blood pressure contribute to the racial differences in patterns of ambulatory blood pressure and should be considered when evaluating patterns of blood pressure in African American youths.
authors.affiliation: Departments of Pediatrics, Medical College of Georgia, Augusta, Georgia 30912-4534, USA. Gharshfi@mail.mcg.edu
authors.forename: G A
authors.initials: GA
authors.lastname: Harshfield
authors.forename: P
authors.initials: P
authors.lastname: Barbeau
authors.forename: P A
authors.initials: PA
authors.lastname: Richey
authors.forename: B S
authors.initials: BS
authors.lastname: Alpert
mesh_terms: D000293:Adolescent; D000367:Age Factors; D044383:Black People; D001794:Blood Pressure / Q000502:physiology; D018660:Blood Pressure Monitoring, Ambulatory; D001824:Body Constitution / Q000502:physiology*; D015992:Body Mass Index; D001830:Body Surface Area; D001835:Body Weight; D002648:Child; D002940:Circadian Rhythm; D005260:Female; D006801:Humans; D008297:Male; D008954:Models, Biological; D044469:Racial Groups; D012044:Regression Analysis; D012737:Sex Factors; D044465:White People; D001741:Black or African American