Obesity Boosts Risk for Persistent Pain After Car Crash

Fran Lowry

May 15, 2014

TAMPA, Florida — Overweight and obese individuals have an increased risk of having persistent moderate or severe neck pain after a motor vehicle collision that can last up to a year.

This finding should be one more reason to get overweight individuals to lose weight, Ana L. Bermudez, MD, from the Department of Anesthesiology, University of North Carolina, Chapel Hill, told Medscape Medical News.

"An increased body mass index increases the risk of persistent moderate or severe axial and overall pain, and that association rises as BMI [body mass index] rises," Dr. Bermudez said here at the American Pain Society (APS) 63rd Annual Scientific Meeting.

"The association is very strong for morbid obesity, and we can definitely see that obesity does have an influence on the development of pain after a motor vehicle accident so it is definitely something to take into account for anyone who is overweight," she said.

Dr. Bermudez and her team studied 916 patients who were seen in their emergency department after sustaining injuries in a motor vehicle collision. Of these patients, 340 (37%) had a normal BMI (18.5 to 24.9 kg/m2), 296 patients (32%) were overweight (BMI, 25.0 to 29.9 kg/m2), 162 (18%) were obese (BMI, 30.0 to 34.5 kg/m2), and 118 (13%) were morbidly obese (BMI, ≥35.0 kg/m2).

Dr. Ana L. Bermudez

The patients were of European descent, aged 18 to 65 years, who presented to the emergency department within 24 hours after their motor vehicle collision.

The researchers assessed patients' overall and axial pain in the neck, right and left shoulders, and upper or lower back via an in-person interview in the emergency department, and later by telephone at 6 months and 1 year, using the Numeric Rating Scale (NRS). On the NRS, 0 means no pain, and 10 means the worst possible pain.

Pain severity of 4 or greater was defined as moderate to severe.

The results showed that obese and morbidly obese individuals were at increased risk for persistent pain at 6 months and 1 year and that the risk appeared to increase in a stepwise fashion with increasing BMI category.

Table 1. Relative Risk for Moderate to Severe Axial Pain After Motor Vehicle Crash

BMI RR at 6 Months (95% CI) RR at 1 Year (95% CI)
Normal weight Reference Reference
Overweight 1.2 (0.92 - 1.5) 1.0 (0.78 - 1.3)
Obese 1.4 (1.1 - 1.8) 1.2 (0.94 - 1.6)
Morbidly obese 1.9 (1.4 - 2.4) 1.4(1.1 - 1.9)

CI = confidence interval; RR = relative risk.


Table 2. Relative Risk for Moderate to Severe Overall Pain After Motor Vehicle Crash

BMI RR at 6 Months (95% CI) RR at 1 Year (95% CI)
Normal weight Reference Reference
Overweight 1.1 (0.91 - 1.4) 1.0 (0.84 - 1.3)
Obese 1.3 (1.0 - 1.7) 1.3 (0.99 - 1.6)
Morbidly obese 1.7 (1.3 - 2.1) 1.4 (1.1 - 1.8)


Dr. Edward Michna


"With obesity come more problems with back pain and chronic pain issues," said Edward Michna, MD, from Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, asked by Medscape Medical News to comment on the study.

"It wouldn't surprise me that after a motor vehicle accident that you would be more predisposed to having more chronic pain issues if you were obese," he said.

This study was funded by the National Institutes of Health-National Institute of Arthritis and Musculoskeletal and Skin Diseases. Dr. Bermudez and Dr. Michna have disclosed no relevant financial relationships.

American Pain Society (APS) 33rd Annual Scientific Meeting. Abstract 235. Presented May 1, 2014.


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