Same Arthritis. But Some Feel More Pain

The X-rays look very similar for two 60-year-old women with arthritic knees.

But the less-educated woman has more severe pain than the person who graduated college.

A new study of men and women finds that the degree of knee-joint deterioration visible in an X-ray isn’t the primary reason one person experiences more knee pain than someone else. Instead, the overwhelming reason is knee strain caused by obesity and the toll taken by physically demanding jobs – both of which are more common among less-educated workers.

The researchers focused on knee arthritis, because musculoskeletal pain is one of the leading causes of Social Security benefit payments to people who develop a disability and can no longer work.

Understanding what’s behind the pain differences is important, because the need for workers in certain jobs requiring physical strength – home health aides, janitors, and construction workers are examples – is expected to increase in the future.

Given this growing demand and predictions of a continued rise in obesity, the researchers conclude that “pain is expected to contribute to an increase” over time in the percentage of the population who will be impaired by their pain.

The people in the study fell into three educational groups: a high school degree or less; some college; or a four-year college degree. The researchers also had information about their occupations, as well as several data sources that gauge the severity of their knee pain, including the ability to do things like walking a quarter of a mile.

Knee arthritis worsens with age. However, a surge in reports of severe knee pain came about a decade earlier for people with no more than a high school degree than the surge for college graduates.

This led to an equally stark difference in who is receiving benefits: 18 percent of the least-educated people between 55 and 64 with chronic knee pain were on disability – dwarfing the 4 percent of college graduates receiving benefits.

If obesity rates keep rising, the researchers predicted the Social Security disability program may have to adapt to a growing share of workers with musculoskeletal pain.

To read this study, authored by David Cutler, Ellen Meara, and Susan Stewart, see “Socioeconomic Status, Perceptions of Pain, and the Gradient in Disability Insurance.”

The research reported herein was derived in whole or in part from research activities performed pursuant to a grant from the U.S. Social Security Administration (SSA) funded as part of the Retirement and Disability Research Consortium.  The opinions and conclusions expressed are solely those of the authors and do not represent the opinions or policy of SSA, any agency of the federal government, or Boston College.  Neither the United States Government nor any agency thereof, nor any of their employees, make any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of the contents of this report.  Reference herein to any specific commercial product, process or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply endorsement, recommendation or favoring by the United States Government or any agency thereof.