Individuals with chronic headache and episodic headache may have a higher prevalence of back pain compared with patients with no headache, and back pain may be associated with lower cephalic and extracephalic pressure pain thresholds in patients with chronic vs episodic headache or no headache, according to a study published in the European Journal of Pain.
Investigators randomly selected individuals from the Danish Civil Registration System (n=796) to complete a headache interview based on the first edition of the International Classification of Headache Disorders, with questions targeting migraine and total tenderness score.
Participants were asked to complete a self-administered questionnaire to obtain information on prevalence of low back pain, education level, self-rated overall health status, daily headache-related disability, and the impact of chronic and episodic headache on daily activities.
In this study, chronic headache was defined as ≥15 headache days per month and episodic headache was defined as <15 headache days per month. Pericranial total tenderness score and cephalic and extracephalic pressure pain threshold data were available for 495 and 494 patients, respectively.
Participants with back pain in the last year were younger than those reporting no back pain (48.3±13.6 vs 51.3±14.4 years; P =.008). At 1 year, a greater percentage of participants with chronic headache and episodic headache had a higher relative frequency of back pain vs individuals with no headaches (82.5% and 80.1% vs 65.7%, respectively). In addition, total tenderness scores were higher in participants with back pain and chronic headache compared with participants with back pain and episodic headache (26.3±12.1 vs 18.5±10.0; P <.001).
Temporalis pressure pain threshold was lower in study participants with back pain who reported chronic vs episodic headache or no headache (169.3±57.8 vs 225.2±98.1; P =.02 and 244.3±105.4; P =.01, respectively). Finger pressure pain threshold was also lower in patients with back pain and chronic headache vs in those with back pain and episodic headache or no headache (237.1±106.7 vs 291.3±141.3; P =.02 and 304.3±137.4; P <.001, respectively).
The cross-sectional nature of the study prevents establishing a causal link between back pain and the chronification of tension-type headache and migraine. In addition, self-reported data may be prone to recall error, further limiting the findings of this analysis.
“Back pain is associated with increased cephalic and extracephalic pain sensitivity in persons with [chronic headache] suggesting central sensitization may be a substrate or consequence of this comorbidity,” concluded the study authors.
Ashina S, Lipton RB, Bendtsen L, et al. Increased pain sensitivity in migraine and tension-type headache coexistent with low back pain: a cross-sectional population study [published online January 19, 2018]. Eur J Pain. doi: 10.1002/ejp.1176