Abstract| Volume 15, ISSUE 4, SUPPLEMENT , S34, April 2014

(235) Obesity increases the risk of persistent moderate or severe neck pain 6 months after motor vehicle collision

      Evidence suggests that body mass index (BMI) may influence the risk of an individual transitioning from acute to chronic musculoskeletal pain. In this study we evaluated the influence of BMI on risk of developing persistent moderate or severe musculoskeletal neck pain (MSMNP) 6 months after a motor vehicle collision (MVC). European Americans age ≥18 and <65 years presenting to the emergency department (ED) within 24 hours of MVC and discharged to home after ED evaluation were enrolled. Participant’s height and weight data, collected via ED interview, were used to calculate BMI. BMI categories (underweight, normal, overweight, and obese) were defined using standard CDC cut-offs. Neck pain (0-10 NRS) was assessed in the ED via in-person interview and at 6 month follow-up via telephone interview or web-based questionnaire. NRS score ≥4 was defined as MSMNP. Participants reporting pain at 6 month follow-up were asked if the pain was MVC-related and only MVC-related pain was included in the data analyses. Height and weight data was available for 934/948 (99%) of enrolled ED patients, and 840/948 (89%) completed 6 month follow-up evaluation. While BMI was not associated with acute neck pain severity (F=0.389 p=0.76), baseline BMI category predicted persistent MSMNP 6 months after MVC (4/16 (25%)) underweight [RR vs. normal weight 1.4 [95%CI 0.6-3.4], 52/293 (18%) normal weight, 47/252 (19%) overweight (RR 1.1, 95%CI [0.7-1.5]), and 69/250 (28%) obese individuals (RR 1.6, 95%CI [1.1-2.3]), (χ2=9.3, p=0.025). These results remained essentially unchanged after adjusting for age and sex. In addition, obese individuals reported a greater number of body regions with persistent MVC-related pain at 6 months (2.01 vs. 2.55, F=4.25, p=0.04). BMI category alone was a poor predictor of persistent MSMNP presence vs. absence (AUROCC=0.565), indicating that weight status is a significant but non-deterministic predictor of MSMNP outcome. Supported by NIAMS R01AR056328.