title: The association between blood pressure and years of schooling versus educational credentials: test of the sheepskin effect.
abstract: OBJECTIVE
  Attaining a degree may offer greater opportunities for health than years of schooling alone. This study examines whether there is a degree, or "sheepskin," effect on the association between education and blood pressure.
  
  
  METHODS
  Multivariable-adjusted ordinal and linear regression models assessed associations of years of schooling and degree attainment with systolic and diastolic blood pressure in a sample of 552 adults ages 38 to 47 years.
  
  
  RESULTS
  Years of schooling was inversely associated with systolic blood pressure adjusting for age, gender and race (β = -0.4, 95% confidence limit: -0.7, -0.1 mmHg systolic blood pressure/year of schooling). Additional adjustment for mother's education, childhood verbal intelligence quotient, childhood health, and childhood socioeconomic status had minimal impact on effect size (β = -0.3, 95% confidence limit = -0.7, 0.0). However, years of schooling was no longer associated with blood pressure in the fully adjusted model which included additional adjustment for degree attained (β = 0.0, 95% confidence limit: -0.5, 0.4). In the fully adjusted model (including adjustment for years of schooling), individuals with a graduate degree still had significantly lower systolic blood pressure than HS degree-holders (e.g., β = -9.2, 95% confidence limit: -15.2, -3.2 for graduate vs high school degree). Findings were similar for diastolic blood pressure.
  
  
  CONCLUSIONS
  The association of years of schooling with blood pressure may be largely due to degree attainment rather than simply the knowledge and skills accumulated due to years of schooling alone.
authors.affiliation: Department of Community Health, Brown Medical School, Providence, RI, USA. szeliu@harvard.hsph.edu
authors.forename: Sze Yan
authors.initials: SY
authors.lastname: Liu
authors.forename: Stephen L
authors.initials: SL
authors.lastname: Buka
authors.forename: Crystal D
authors.initials: CD
authors.lastname: Linkletter
authors.forename: Ichiro
authors.initials: I
authors.lastname: Kawachi
authors.forename: Laura
authors.initials: L
authors.lastname: Kubzansky
authors.forename: Eric B
authors.initials: EB
authors.lastname: Loucks
mesh_terms: D000328:Adult; D001794:Blood Pressure; D015331:Cohort Studies; D004522:Educational Status; D005260:Female; D006304:Health Status; D006801:Humans; D006973:Hypertension / Q000453:epidemiology; D008297:Male; D008404:Massachusetts / Q000453:epidemiology; D008875:Middle Aged; D012044:Regression Analysis; D012237:Rhode Island / Q000453:epidemiology; D012307:Risk Factors