Background Fibromyalgia (FM) is a chronic condition characterized by widespread musle pain and tenderness. Chronic pain is the major symptom that affects patients physically, mentally and socially. Mechanisms of pain in FM are not completely understood. Relation between smoking and pain is contradictive. In epidemiologic studies smoking is associated to chronic pain, while in acute experiment stimulation of nicotine receptors alleviates pain.
Objectives The present study evaluates the possible relation between pain, cigarette smoking, and levels of IGF-1 in patients with FM.
Methods Pain was characterised in 63 patients with FM (all women, age 52 years) by Fibromialgia Impact Questionnaire (FIQ), tender points count, and pain threshold was assessed by algometer. All patients participated in the structured telephone interview regarding their smoking habits. Levels of IGF-1, leptin, resistin, and adiponectin were measured in blood. The statistical analysis was performed regarding smoking habits, IGF-1 levels and intensity of pain. Patients were categorized by pain (FIQ and threshold) quartiles, and relative risk (95%CI) was calculated.
Results Eighteen patients (28.6%) reported to be current smokers, and 45 were non-smokers. Among the non-smokers, 25 patients smoked previously and ceased before the study (median 13 years, range 1-30). Smokers had higher pain experience compared to non-smokers, characterised by higher FIQ (p=0.036), and lower pain threshold (p=0.014). The difference in pain was largest between the current smokers and patients who had ceased smoking (dFIQ 12%, p=0.005). The RR of pain in the upper quartile in smokers was 6.3 (95%CI: 1.41-36.18) compared to previous smokers. Furthermore, previous smokers have lower pain, fewer tender points and a higher pain threshold compared to smokers. Smokers had significantly lower levels of IGF-1 (ng/ml, median: 2.72 vs 4.82, p=0.027) compared to never-smokers and lower levels of leptin (ng/ml, median: 16.9 vs 34.8, p=0.013) compared to non-smokers. Current and previous smokers had frequently low levels of IGF-1 compared to non-smokers (88% vs 12%, p=0.018).
Conclusions Smoking in FM patients was associated with high pain experience. Pain experience improved in the patients who had ceased smoking. Current and previous smoking was associated with low levels of IGF-1 suggesting long-term effects of smoking on regulation of IGF-1 levels in FM patients.
Disclosure of Interest None Declared