The prevalence of spontaneous endometriosis in the baboon (Papio anubis, Papio cynocephalus) increases with the duration of captivity

Abstract

It is not known whether stress affects the prevalence of endometriosis in women. Baboons with spontaneous endometriosis may be interesting models to study the human disease. For baboons, living in captivity is a period of chronic stress without continuous exposure to pregnancy. This study was done to compare the prevalence of endometriosis between baboons recently captured in the wild and those living in captivity for several years. A diagnostic laparoscopy was performed for screening endometriosis and obtaining biopsies in 104 female baboons including animals that had been captured in the wild less than 1 year ago (n=52, Group I), primates that had been living in captivity for one to two years (n=30, Group II) and animals that had been captured for more than two years (n=22, Group III). The prevalence of clinical and biopsy-proven endometriosis in all baboons was 17% and 12%, respectively. Clinical endometriosis was found more frequently in group III (32%) than in group II (17%) or group I (11%). The prevalence of biopsy-proven endometriosis was also significantly higher in group III (27%) than in groups I and II combined (8%, p=0.03). The results indicate that the prevalence of endometriosis increases with the time spent in captivity. This trend may be explained by more menstrual cycles uninterrupted by pregnancy in captive than in wild baboons, and possibly also by age-related factors or by captivity-associated stress.