[ASSOCIATION OF OBESITY, SMOKING AND SOCIOECONOMIC STRATA WITH THE FIBROMYALGIA SYNDROME].

Aims: This study aimed to examine a possible association between BMI levels, smoking and socio-economic status and the existence of fibromyalgia.

Background: Obesity is a worldwide epidemic with devastating impacts on the public's health. There are several indications that obesity might also be involved in the pathogenesis of chronic pain syndromes such as fibromyalgia.

Methods: Patients who were diagnosed with fibromyalgia were compared to population-based controls, matched in age and gender (by a ratio of 1:5). Body mass indices, smoking status and socioeconomic strata were retrieved from computerized medical records of the Clalit Health Services database. Body mass index was classified in WHO categories of underweight, normal, overweight and obese (<18.5, 18.5-<25, 25.0-<30, ≥30.0 kg/m2); χ2, t-tests, and logistic regression models were used to compare the study groups and assess the association between obesity and fibromyalgia.

Results: The study included 14,296 patients with fibromyalgia and 71,324 controls. Among patients with fibromyalgia the average BMI (body mass index) was higher than that of the controls 29.1± 6.2 vs. 28.0± 6.01, p<0.001) with every increment of 1 unit of the BMI score, there was an increment of 2.7% of the odds of having coexistent fibromyalgia. The chances of having fibromyalgia was 56% higher among subjects with obesity compared to individuals of normal weight. The data revealed that patients with fibromyalgia smoke more and belong to lower socioeconomic levels.

Conclusions: Our findings demonstrate that obesity is significantly associated with a higher proportion of fibromyalgia. This finding underlines the role that obesity plays in inflammation and chronic pain.