title: Are low wages risk factors for hypertension?
abstract: OBJECTIVE
  Socio-economic status (SES) is strongly correlated with hypertension. But SES has several components, including income and correlations in cross-sectional data need not imply SES is a risk factor. This study investigates whether wages-the largest category within income-are risk factors.
  
  
  METHODS
  We analysed longitudinal, nationally representative US data from four waves (1999, 2001, 2003 and 2005) of the Panel Study of Income Dynamics. The overall sample was restricted to employed persons age 25-65 years, n = 17 295. Separate subsamples were constructed of persons within two age groups (25-44 and 45-65 years) and genders. Hypertension incidence was self-reported based on physician diagnosis. Our study was prospective since data from three base years (1999, 2001, 2003) were used to predict newly diagnosed hypertension for three subsequent years (2001, 2003, 2005). In separate analyses, data from the first base year were used to predict time-to-reporting hypertension. Logistic regressions with random effects and Cox proportional hazards regressions were run.
  
  
  RESULTS
  Negative and strongly statistically significant correlations between wages and hypertension were found both in logistic and Cox regressions, especially for subsamples containing the younger age group (25-44 years) and women. Correlations were stronger when three health variables-obesity, subjective measures of health and number of co-morbidities-were excluded from regressions. Doubling the wage was associated with 25-30% lower chances of hypertension for persons aged 25-44 years.
  
  
  CONCLUSIONS
  The strongest evidence for low wages being risk factors for hypertension among working people were for women and persons aged 25-44 years.
authors.affiliation: Department of Public Health Sciences, University of California Davis School of Medicine, CA, USA. pleigh@ucdavis.edu
authors.forename: J Paul
authors.initials: JP
authors.lastname: Leigh
authors.forename: Juan
authors.initials: J
authors.lastname: Du
mesh_terms: D000328:Adult; D017677:Age Distribution; D000368:Aged; D005260:Female; D015438:Health Behavior; D006801:Humans; D006973:Hypertension / Q000453:epidemiology* / Q000209:etiology / Q000523:psychology; D015994:Incidence; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000453:epidemiology; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012111:Residence Characteristics; D012307:Risk Factors; D012456:Salaries and Fringe Benefits; D017678:Sex Distribution; D012923:Social Class; D012959:Socioeconomic Factors; D013315:Stress, Psychological; D014481:United States / Q000453:epidemiology