title: Cigarette Smoking and Subtypes of Uncontrolled Blood Pressure Among Diagnosed Hypertensive Patients: Paradoxical Associations and Implications.
abstract: BACKGROUND
  Isolated uncontrolled systolic blood pressure (SBP), uncontrolled systolic-diastolic blood pressure (BP), and isolated uncontrolled diastolic blood pressure (DBP) are subtypes of uncontrolled BP. The associations of smoking with uncontrolled BP subtypes among diagnosed hypertensive patients are unknown.
  
  
  METHODS
  Seven thousand eight hundred twenty-nine subjects aged 18 years or over with diagnosed hypertension were selected from the National Health and Nutrition Examination Survey with stratified multistage clustered sampling design. Weighted logistic regressions were conducted to estimate odds ratios (ORs) with 95% confidence intervals (CIs) of uncontrolled BP subtypes related to smoking status. Weighted multiple regression models were used to examine the association of smoking with levels of SBP, DBP, and pulse pressure.
  
  
  RESULTS
  The average age of the study sample was 60.3 ± 0.3 years. 54.2% ± 0.7% were females. Compared to nonsmokers, current smokers were 22% less likely to have uncontrolled BP (OR: 0.78, 95% CI: 0.64-0.94, P = 0.01), and 21% less likely to have isolated uncontrolled SBP (OR: 0.79, 95% CI: 0.64-0.97, P = 0.02). Average DBP was 1.5 mm Hg lower (95% CI: -2.8 to -0.2 mm Hg, P = 0.02) in current smokers than in nonsmokers. Average DBP was 0.9 mm Hg lower (95% CI: -1.7 to -0.03 mm Hg, P = 0.04) in former smokers than in nonsmokers. Current smoking and former smoking were not associated with risk of uncontrolled systolic-diastolic BP and isolated uncontrolled DBP.
  
  
  CONCLUSIONS
  Paradoxical associations between current smoking and SBP, uncontrolled BP and isolated uncontrolled SBP were shown among hypertensive patients. The explanation for these associations is currently unknown. No cause-effect relationships should be assumed.
authors.affiliation: Department of Systems, Population, and Leadership, School of Nursing, University of Michigan, Ann Arbor, Michigan, USA.
authors.forename: Xuefeng
authors.initials: X
authors.lastname: Liu
authors.affiliation: Division of Cardiovascular Medicine, University of Michigan Health System, Ann Arbor, Michigan, USA.
authors.forename: James Brian
authors.initials: JB
authors.lastname: Byrd
mesh_terms: D000293:Adolescent; D000328:Adult; D000959:Antihypertensive Agents / Q000627:therapeutic use*; D001794:Blood Pressure / Q000187:drug effects*; D016009:Chi-Square Distribution; D003430:Cross-Sectional Studies; D004351:Drug Resistance; D004359:Drug Therapy, Combination; D005260:Female; D006801:Humans; D006973:Hypertension / Q000175:diagnosis / Q000188:drug therapy* / Q000453:epidemiology / Q000503:physiopathology; D016014:Linear Models; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009749:Nutrition Surveys; D016017:Odds Ratio; D018570:Risk Assessment; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects* / Q000453:epidemiology; D013997:Time Factors; D014481:United States / Q000453:epidemiology; D055815:Young Adult
chemical_list: D000959:Antihypertensive Agents
keywords: blood pressure; hypertension; isolated uncontrolled diastolic blood pressure; isolated uncontrolled systolic blood pressure; smoking; uncontrolled blood pressure; uncontrolled systolic–diastolic blood pressure