Association between alcohol consumption and chronic pain: a systematic review and meta-analysis
Roya Karimi, Narmeen Mallah, Saharnaz Nedjat, Marcus Beasley, Bahi Takkouche
Abstract
Introduction: Chronic pain represents a global health problem with a considerable economic burden. The relation of alcohol intake and chronic pain conditions was assessed in several studies with conflicting results. We used doseeresponse meta-analysis techniques to answer the question of whether alcohol intake is related to chronic pain occurrence. Methods: We searched MEDLINE, Embase, and other databases to identify cohort and case-control studies on alcohol consumption and chronic pain. Sixteen studies were eligible with a total population of 642 587 individuals. Fixed-effects and random-effects pooled estimates were obtained by weighting log odds ratios (ORs) in case-control studies and log incidence rate ratios in cohort studies by the inverse of their variance. A heterogeneity assessment and a doseeresponse analysis were carried out. Quality scoring was also performed. Results: Our results show that any alcohol consumption was related to lower odds of chronic pain (pooled OR0.76; 95% confidence interval [CI], 0.61e0.95). The association was non-linear. The ORs by quartile of alcohol doses were as follows: OR 2nd quartile 0.74; 95% CI, 0.64e0.87; OR 3rd quartile 0.67; 95% CI, 0.53e0.86; and OR 4th quartile0.75; 95% CI, 0.50e1.14. This association was observed for cohort studies (OR0.77; 95% CI, 0.61e0.98) and European studies (OR0.65; 95% CI, 0.48e0.87) only. Studies with complete adjustment for confounding factors showed a stronger relation than those with incomplete adjustment (OR0.69; 95% CI, 0.48e0.99 and OR0.85; 95% CI, 0.65e1.11, respectively). Conclusion: Alcohol consumption presents a non-linear inverse association with the occurrence of chronic pain. Although plausible mechanisms could explain this protective effect, other explanations, including reverse causation, are probable.