COX-2 gene -1195G>A polymorphism (rs689466) is associated with dysmenorrhea among Nigerian women

Dysmenorrhea with its debilitating effects is a major reproductive disorder experienced by adolescents and young women. Individual differences in the experience and severity of dysmenorrhea and response to NSAIDs suggest that genetic variations in prostaglandin synthesis may play a role. We therefore examined a possible relationship between cyclooxygenase-2 (COX-2) -1195G>A gene polymorphism (rs689466) and menstrual pain. Adolescents and young women of reproductive age (n = 102) were recruited for the study. The participants were given questionnaires to obtain information on their menstrual cycles and pain rating scales to rate the pain experienced during their menstrual periods. In addition, genotype analysis was done by PCR-RFLP method and statistical analysis was carried out to assess the interaction between the self-reported presence and severity of dysmenorrhea and genotype. Dysmenorrhea was reported by 67 (65.7%) of the participants while 35 (34.3%) reported no pain. Among those who reported pain, 5 (7.5%), 28 (5.8%) and 34 (50.7%) reported mild, moderate and severe pain respectively. The frequencies of G and A alleles were 163 and 41 while the frequencies of GG, GA and AA were 70, 23 and 9 respectively. The population was not in Hardy-Weinberg equilibrium (χ2 = 9.053, df = 1, p = 0.003). Carriers of the A allele were more than thrice as likely to report pain as those with no A allele (OR = 3.07, p = 0.025). The presence of an A allele of COX-2 gene -1195G>A polymorphism may predispose to dysmenorrhea. •-1195G>A polymorphism of the COX-2 gene may contribute to differences in the experience and severity of dysmenorrhea.•The GG genotype was the most frequent among the women studied and the distribution was not in Hardy-Weinberg equilibrium.•Presence of an A allele was associated with increased incidence of dysmenorrhea and its severity.•Carriers of the A allele are more than three times as likely to experience dysmenorrhea.