This study is to evaluate the association between the catechol-O-methyltransferase (COMT) gene val(158)met polymorphism and FM risk. We performed a meta-analysis of 8 case-control studies that included 589 FM cases and 527 case-free controls. We assessed the strength of the association, using odds ratios (ORs) with 95% confidence intervals (CIs). Overall, this meta-analysis showed that the COMT gene val(158)met polymorphism was not associated with FM risk in all genetic models, i.e., allele (met vs. val: OR=1.46, 95% CI=0.80-2.66, P heterpgeneity<0.001), homozygous (met/met vs. val/val: OR=1.72, 95% CI=0.61-4.87, P heterpgeneity<0.001), heterozygous (val/met vs. val/val: OR=1.25, 95% CI=0.82-1.92, P heterpgeneity=0.050), recessive (met/met vs. val/val+val/met: OR=1.52, 95% CI=0.60-3.86, P heterpgeneity<0.001) and dominant model (met/met+val/met vs. val/val: OR=1.52, 95% CI=0.80-2.90, P heterpgeneity<0.001). Similarly, there were no significant associations in the subgroup analyses by ethnicity and HWE. No publication bias was found in the present study. This meta-analysis suggests that the COMT gene val(158)met polymorphism is not associated with FM risk. Further large and well-designed studies are needed to confirm this association.
Keywords: Fibromyalgia; catechol-O-methyltransferase; meta-analysis; polymorphism.