CAFFEINE AND CHRONIC BACK PAIN

Objective: Tobacco use and other behavioral factors are associated wit h chronic back pain. Anecdotes suggest excess caffeine use may also be associated with chronic back pain. We compared caffeine consumption b y chronic back pain patients with caffeine consumption by controls. De sign: Retrospective case-control study. Setting: A multispecialty outp atient facility. Patients: Sixty new, consecutive patients with chroni c back pain compared to 60 new, consecutive patients without chronic b ack pain. Intervention: Patients were prospectively asked to complete an intake questionnaire. Main Outcome Measure: Daily caffeine consumpt ion was estimated by analyzing the intake questionnaire. Differences b etween groups were analyzed by both normal and nonparametric statistic s. Results: Consumption of caffeine by patients with chronic back pain averaged 392.4 mg/day. Controls consumed 149.8 mg/day, a significant difference (p = .0001). Men consumed 86% more caffeine per day than wo men (p = .02). Age and caffeine consumption showed little correlation (r = .126). Conclusions: Patients with chronic back pain consume over twice as much caffeine as patients without chronic back pain. Confound ing variables and possible mechanisms associating caffeine with chroni c back pain are discussed. (C) 1997 by the American Congress of Rehabi litation Medicine and the American Academy of Physical Medicine and Re habilitation