Open Access Research article

Associations of educational attainment, occupation and community poverty with knee osteoarthritis in the Johnston County (North Carolina) osteoarthritis project

Leigh F Callahan1*, Rebecca J Cleveland1, Jack Shreffler1, Todd A Schwartz2, Britta Schoster1, Randy Randolph3, Jordan B Renner4 and Joanne M Jordan1

Author Affiliations

1 Thurston Arthritis Research Center, Departments of Medicine and Social Medicine, 3300 Thurston Building, CB # 7280, University of North Carolina, Chapel Hill, NC 27599-7330, USA

2 Department of Biostatistics, Gillings School of Global Public Health, University of North Carolina, 3106E McGavran-Greenberg Hall, CB #7420, Chapel Hill, NC 27599-7420, USA

3 Sheps Center for Health Services Research, 725 Martin L King Jr Blvd, Campus Box 7590, University of North Carolina, Chapel Hill, NC 27599-7590, USA

4 Department of Radiology, University of North Carolina, 509 Old Infirmary Bldg, Campus Box 7510, Chapel Hill, NC 27599, USA

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Arthritis Research & Therapy 2011, 13:R169  doi:10.1186/ar3492

Published: 19 October 2011

Abstract

Introduction

The purpose of this study was to examine data from the Johnston County Osteoarthritis (OA) Project for independent associations of educational attainment, occupation and community poverty with tibiofemoral knee OA.

Methods

A cross-sectional analysis was conducted on 3,591 individuals (66% Caucasian and 34% African American). Educational attainment (< 12 years or ≥12 years), occupation (non-managerial or not), and Census block group household poverty rate (< 12%, 12 to 25%, > 25%) were examined separately and together in logistic models adjusting for covariates of age, gender, race, body mass index (BMI), smoking, knee injury and occupational activity score. Outcomes were presence of radiographic knee OA (rOA), symptomatic knee OA (sxOA), bilateral rOA and bilateral sxOA.

Results

When all three socioeconomic status (SES) variables were analyzed simultaneously, low educational attainment was significantly associated with rOA (odds ratio (OR) = 1.44, 95% confidence interval (CI) 1.20, 1.73), bilateral rOA (OR = 1.43, 95% CI 1.13, 1.81), and sxOA (OR = 1.66, 95% CI 1.34, 2.06), after adjusting for covariates. Independently, living in a community of high household poverty rate was associated with rOA (OR = 1.83, 95% CI 1.43, 2.36), bilateral rOA (OR = 1.56, 95% CI 1.12, 2.16), and sxOA (OR = 1.36, 95% CI 1.00, 1.83). Occupation had no significant independent association beyond educational attainment and community poverty.

Conclusions

Both educational attainment and community SES were independently associated with knee OA after adjusting for primary risk factors for knee OA.

Keywords:
knee osteoarthritis; educational attainment; occupation; community poverty; socioeconomic status