Background: We sought to assess vulvodynia incidence and risk factors among those with and without premorbid urogenital symptoms.
Methods: Women's Health Registry members who completed a baseline assessment in 2004 were sent a 2-year and 4-year follow-up survey containing a validated screen for vulvodynia. Subgroup analysis of vulvodynia incidence rates was performed, and risk factors associated with incidence were assessed.
Results: Of 1037 original enrollees, 723 (69.7%) completed consecutive surveys (initial and 2-year or initial, 2-year, and 4-year), 660 of whom did not have current or past vulvodynia at baseline. Of these 660, 71 (10.8%) first met criteria for vulvodynia within the 4-year period, for an annual incidence rate of 3.1% (95% confidence interval [CI] 2.5-4.0). Baseline strict controls were less likely to develop criteria for vulvodynia diagnosis (annual incidence rate of 1.4%) compared to those with an intermediate phenotype (presence of dyspareunia or history of short-term vulvar pain), for whom the incidence rate was 5.6% (p<0.001). Risk factors for incident vulvodynia differed between these two groups. Among the strict controls, an increased risk was noted among younger women (incidence rate ratio) [IRR] 3.6). For those with an intermediate phenotype, risk was increased among nonwhite women and those reporting pain with or after intercourse (IRR 2.2, 3.4, and 3.1, respectively). In both control groups, incident vulvodynia risk increased among those reporting urinary burning at enrollment (IRR 4.2 and 2.8 for strict and intermediate phenotype controls, respectively).
Conclusions: The annual incidence of vulvodynia is substantial (3.1%) and is greater among women reporting a history of dyspareunia or vulvar pain that did not meet criteria for vulvodynia compared to those without this history, suggesting that generalized urogenital sensitivity may be a common underlying mechanism predating the clinical presentation of vulvodynia.