Socioeconomic Status, Perceptions of Pain, and the Gradient in Disability Insurance
Reports of physical and mental pain differ markedly across socioeconomic groups. Musculoskeletal pain, the leading reason for new disability awards, is more prevalent among less educated people. This paper examines the differential experience of pain by education. We consider gaps in the rate of physical illness or injury, differences in behavioral or environmental factors that exacerbate pain, and factors that could mitigate pain differently across education groups. We focus on musculoskeletal pain, and in particular knee pain, the most common musculoskeletal complaint in population-based surveys. Comparing clinical interpretation of x-rays of knees evaluated for arthritis, there are remarkably few differences in presence or clinical severity of arthritis across education groups. In contrast, for any given objective measure of disease, less educated people report more knee pain. After confirming that reported pain maps to objective measures like walking speed, range of motion, and specific aspects of function, we test whether obesity, physically demanding occupations, or psychological factors more common among less educated individuals explain some of the gap in reported knee pain. Together, physical demands on the job and obesity explain nearly two-thirds of the education gradient in knee pain. In contrast, other job characteristics and psychological traits related to negative affect, life satisfaction, sense of control, and psychological well-being explain almost none of the educational gradient in knee pain. As physically demanding occupations like home health aides, personal service workers, janitorial services and construction are predicted to grow in coming decades, and given steady rise in obesity in the population, pain is expected to contribute to an increase in disability over time.