title: Relationship of urinary sodium/potassium excretion and calcium intake to blood pressure and prevalence of hypertension among older Chinese vegetarians.
abstract: OBJECTIVE
  To examine the associations of dietary sodium and potassium, as reflected by the urinary sodium/potassium excretion, and calcium intake with blood pressure and the prevalence of hypertension among older Chinese vegetarians in Hong Kong.
  
  
  METHODS
  Cross-sectional study.
  
  
  METHODS
  Research clinic in a teaching hospital in Hong Kong.
  
  
  METHODS
  A total of 111 ambulatory vegetarians over the age of 55 were recruited from members of religious organizations or old age hostels.
  
  
  METHODS
  Hypertension was defined as supine blood pressure >140/90 mmHg or a history of hypertension. Dietary sodium, potassium and calcium intakes were assessed by 24 h recall method or fasting urinary sodium or potassium/creatinine ratios.
  
  
  RESULTS
  Seventy-one subjects (64%) were found to have hypertension. Compared with normotensive subjects, hypertensive subjects had lower calcium intake (411+/-s.d. 324 vs 589+/-428 mg, P=0.04), but higher urinary sodium/creatinine ratio (32.6+/-19.3 vs 21.0+/-12.4, P=0.00) and sodium/potassium ratio (4.7+/-2.8 vs 3.4+/-2.3, P=0.02). Among 88 subjects not taking diuretics or antihypertensive drugs, systolic blood pressure was related to calcium intake (r=-0.40), urinary sodium/creatinine ratio (r=0.39), urinary sodium/potassium ratio (r=0.30) and age (r=0.23). Diastolic blood pressure was related to urinary sodium/creatinine (r=0.29). Twenty-three subjects with high urinary sodium/potassium and low calcium intake and 16 subjects with low urinary sodium/potassium ratio and high calcium intake differed markedly with respect to systolic blood pressure (159+/-26 vs 130+/-15 mmHg) and prevalence of hypertension (78% vs 25%).
  
  
  CONCLUSIONS
  Older Chinese vegetarians are predisposed to hypertension because of their sodium-rich but calcium-deficient diets.
authors.affiliation: Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, New Territories, Hong Kong. tkwok@cuhk.edu.hk
authors.forename: T C Y
authors.initials: TC
authors.lastname: Kwok
authors.forename: T Y K
authors.initials: TY
authors.lastname: Chan
authors.forename: J
authors.initials: J
authors.lastname: Woo
mesh_terms: D000368:Aged; D001794:Blood Pressure / Q000502:physiology*; D002136:Calcium, Dietary / Q000008:administration & dosage* / Q000652:urine; D002681:China / Q000453:epidemiology; D003430:Cross-Sectional Studies; D014676:Diet, Vegetarian / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D006973:Hypertension / Q000453:epidemiology* / Q000652:urine*; D017419:Potassium, Dietary / Q000652:urine*; D015995:Prevalence; D012982:Sodium, Dietary / Q000652:urine*
chemical_list: D002136:Calcium, Dietary; D017419:Potassium, Dietary; D012982:Sodium, Dietary