Risk of pelvic organ prolapse treatment based on extended family history.BACKGROUND
 Family history of pelvic organ prolapse among first-degree relatives is an established risk factor for pelvic organ prolapse; however, consideration of the constellation of family history that extends to distant relationships allows for more accurate determination of risk and may improve pelvic organ prolapse risk prediction estimates.


 OBJECTIVE
 The purpose of this study was to assess risk for pelvic organ prolapse treatment based on varying family histories of pelvic organ prolapse and included number and types of affected relatives, ages of relatives at pelvic organ prolapse treatment, and whether the family history is of maternal or paternal origin.


 This was a retrospective, population-based study that involved the Utah Population Database, which is a population resource that includes extensive genealogy information linked to medical records.  The study population included 453,522 total women: 4628 women with a diagnosis of treated (surgical or pessary) pelvic organ prolapse and their 15,530 first-degree relatives; 33,782 second-degree relatives, and 66,469 third-degree relatives.  We estimated relative risk of treated pelvic organ prolapse based on specific family history constellations.


 Relative risk estimates increased with a family history of increasing numbers of treated first-degree relatives with pelvic organ prolapse (first-degree relatives, ≥1 [relative risk, 2.36; 95% confidence interval, 2.15-2.58], first-degree relatives, ≥2 [relative risk, 3.79; 95% confidence interval, 2.65-5.24], and first-degree relatives, ≥3 [relative risk, 6.26; 95% confidence interval, 1.29-18.30]).  Having a family history of ≥3 affected third-degree relatives (eg, first cousins) and no affected first- or second-degree relatives was similar in risk to having 1 affected first-degree relative.  Relative risk estimates decreased with increasing age of treatment for first-degree family members.  Risks in individuals with a positive maternal family history for pelvic organ prolapse were consistently higher than risks in individuals with equivalent paternal family history, but paternal inheritance still played a role.  Approximately 4% of the total studied female population was found to have a >2-fold risk of being treated for pelvic organ prolapse and is considered high-risk based on their family history.


 CONCLUSION
 We provide estimates for treated pelvic organ prolapse based on an extensive family history of pelvic organ prolapse using a large population-based sample.  Risk for treated pelvic organ prolapse increased with increasing numbers of affected close and distant female relatives, earlier age of pelvic organ prolapse treatment in relatives, and maternal inheritance.  These risk estimates may be useful for genetic studies and investigation of risk reduction strategies in those at highest risk for pelvic organ prolapse.
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