Differences in epigenetic age acceleration according to a diagnosis of endometriosis/adenomyosis: the Norwegian Mother, Father and Child Cohort Study

BACKGROUND: Women with endometriosis and adenomyosis have an increased risk of age-dependent diseases such as cardiovascular disease and cancer. Whether this reflects differences in biological age is unknown. OBJECTIVE: To compare the epigenetic age acceleration between women with endometriosis or adenomyosis to those without these conditions. STUDY DESIGN: We studied 234 women with endometriosis or adenomyosis and 3508 women without these conditions enrolled while pregnant into the Norwegian Mother, Father and Child Cohort Study. Epigenetic age acceleration, estimated using 7 different established clocks based on peripheral blood DNA methylation, was compared between those with and without endometriosis or adenomyosis using linear regression, with adjustment for the woman's chronological age, educational level, smoking status, body mass index, and batch at the time of blood sampling. RESULTS: In the unadjusted analysis, we observed modest epigenetic age deceleration estimated using the Horvath pan-tissue clock among those with endometriosis/adenomyosis compared to those without (mean difference in the z-score, -0.15; 95% confidence interval, -0.28 to 0.02). No notable differences were observed in the estimates of epigenetic age acceleration using the other established clocks, where the mean differences in the z-scores ranged between -0.10 and 0.06. After multivariable adjustment, the significant difference in the Horvath pan-tissue clock was attenuated (mean difference in the z-score, 0.00; 95% confidence interval, -0.13 to 0.13). CONCLUSION: We did not find evidence of meaningful differences in epigenetic age acceleration measured in peripheral blood collected during pregnancy by diagnosis with endometriosis or adenomyosis.