RESUMO
OBJECTIVE: To study further the temporal clustering of ankylosing enthesopathy (AE) noted originally during a study of the influence of mouse major histocompatibility complex (MHC) H-2 and transgenic HLA-B27 on the frequency of AE. METHODS: The relationship between maternal age at littering and frequency of AE was analysed. RESULTS: Mice born to mothers aged eight months or older had a significantly lower disease frequency of AE than mice born to mothers younger than eight months of age. This phenomenon was observed in three independent cohorts evaluated to date (p < 0.01, 0.025, and 0.05). CONCLUSION: Maternal age is a novel, non-genetic risk factor as defined in relation to an MHC associated enthesopathy. Its mode of action and relevance to human disease require further investigation.