To examine the independent and combined influence of individual- and community-level socioeconomic status (SES) measures on physical health status outcomes in people with self-reported arthritis.
From 2004-2005, 968 participants completed a telephone survey assessing health status, chronic conditions, community characteristics, and sociodemographic variables. Individual-level SES measures used included homeownership, occupation (professional or not), educational attainment (less than high school, high school degree, and more than high school), and income (<$15,000, $15,000-$45,000, and >$45,000). Community poverty (2000 US Census block group percentage of individuals living below the poverty line [low, medium, and high]) was used as a community-level SES measure. Outcomes were physical functioning (Medical Outcomes Study Short Form 12 version 2 physical component summary [PCS]), functional disability (Health Assessment Questionnaire [HAQ]), and the Centers for Disease Control and Prevention (CDC) Health-Related Quality of Life (HRQOL) Healthy Days physical and limited activity days, and were analyzed via multivariable regressions.
When entered separately, all individual-level SES variables were significantly (P < 0.01) associated with poorer PCS, HAQ, and CDC HRQOL scores. A higher magnitude of effect was seen for household income, specifically <$15,000 per year in final models with all 4 individual SES measures and community poverty. The magnitude of effect for education is reduced and marginally significant for the PCS and number of physically unhealthy days. No effects were seen for occupation, homeownership, and community poverty.
Findings confirm that after adjusting for important covariates, lower individual- and community-level SES measures are associated with poorer physical health outcomes, while household income is the strongest predictor (as measured by both significance and effect) of poorer health status in final models. Studies not having participant-reported income available should make use of other SES measures, as they do independently predict physical health.