title: The association of waist circumference with ambulatory blood pressure is independent of alternative adiposity indices.
abstract: OBJECTIVE
  The relationship between waist circumference (WC) and conventional blood pressure (BP) is independent of other clinical indices of adiposity. As ambulatory BP may offer more prognostic information than conventional BP, we aimed to identify whether indices of central adiposity are associated with ambulatory BP independent of other indices of adiposity.
  
  
  METHODS
  The relationship between indices of adiposity [WC, waist-to-hip ratio, body mass index (BMI) or skin-fold thickness] and ambulatory or conventional BP was determined in 300 randomly selected individuals of African descent living in an urban developing community in South Africa. Relationships were determined with multiple indices of adiposity in the same regression model and after adjusting for age, gender, alcohol and tobacco intake, the presence or absence of diabetes mellitus or inappropriate blood glucose control [haemoglobin A1c (HbA1c)], antihypertensive therapy and menopausal status.
  
  
  RESULTS
  Sixty-five per cent of participants were overweight or obese. With respect to the relationships between indices of adiposity, BMI and WC showed the strongest correlation (r=0.84, P<0.0001). After including all indices of adiposity and confounders in the model, WC was the only clinical index of adiposity which independently predicted 24-h (partial r=0.15, P<0.005) and conventional (partial r=0.14, P<0.005) systolic BP and 24-h (partial r=0.13, P<0.02) and conventional (partial r=0.40, P<0.0001) diastolic BP. After adjusting for other adiposity indices and confounders, every 1 SD (15 cm) increase in WC resulted in a 4.04 mmHg increase in 24-h systolic BP and a 4.33 mmHg increase in 24-h diastolic BP. Similar results were obtained in the subgroup of 237 participants not receiving antihypertensive therapy.
  
  
  CONCLUSIONS
  WC is the only clinical index of adiposity that is associated with 24-h and conventional BP independent of other adiposity indices in a community with a high prevalence of obesity.
authors.affiliation: Cardiovascular Pathophysiology and Genomics Research Unit, School of Physiology, South Africa.
authors.forename: Olebogeng H I
authors.initials: OH
authors.lastname: Majane
authors.forename: Gavin R
authors.initials: GR
authors.lastname: Norton
authors.forename: Muzi J
authors.initials: MJ
authors.lastname: Maseko
authors.forename: Siyanda
authors.initials: S
authors.lastname: Makaula
authors.forename: Nigel
authors.initials: N
authors.lastname: Crowther
authors.forename: Janice
authors.initials: J
authors.lastname: Paiker
authors.forename: Lutgarde
authors.initials: L
authors.lastname: Thijs
authors.forename: Richard
authors.initials: R
authors.lastname: Brooksbank
authors.forename: Pinhas
authors.initials: P
authors.lastname: Sareli
authors.forename: Jan A
authors.initials: JA
authors.lastname: Staessen
authors.forename: Angela J
authors.initials: AJ
authors.lastname: Woodiwiss
mesh_terms: D050154:Adiposity; D000328:Adult; D001794:Blood Pressure; D018660:Blood Pressure Monitoring, Ambulatory; D015992:Body Mass Index; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D013019:South Africa; D011795:Surveys and Questionnaires