Epigenetic associations with sex hormone levels and cardiometabolic disease risk factors in pre- and post-menopausal women from West Africa

Abstract

Menopause is the permanent decline in ovarian function in women, signifying the discontinuation of reproductive potential. Changes in hormone levels due to the menopausal transition have been found to promote the progression to cardiometabolic diseases. Possible epigenetic mechanisms behind changes in hormone levels during the menopausal transition require further research, especially among underrepresented African populations. This cross-sectional cohort study aims to examine epigenetic mechanisms, specifically DNA methylation, to assess its role in differences in sex hormone levels and the prevalence of cardiometabolic disease in pre-and post-menopausal women from Nanoro, Burkina Faso, in West Africa. Genomic DNA derived from blood samples of 99 pre- and 98 post-menopausal participants from the ‘Africa Wits-INDEPTH Partnership for Genomic Research’ (AWI-Gen) was bisulfite modified in preparation for sequencing and methylation calling. Target-specific PCR products amplified with custom-designed methylation primers for androgen receptor (AR), follicle-stimulating hormone receptor (FSHR), inhibin B (INHBB), sex hormone binding globulin (SHBG) and oestrogen receptor β (ESR2) were purified, tagged with indexes, and pooled before next-generation sequencing. Methylation levels across five CpG islands and 86 CpG sites with high-depth sequencing coverage of ~50 000x were determined bioinformatically with the Illumina DRAGEN Methylation Pipeline through BaseSpace. Differences in demographic, behavioural, epigenetic, hormonal, cardiometabolic, anthropometric, and socioeconomic data between pre- and post- menopausal groups were assessed with the Student’s T-test and Mann-Whitney U- test. Bivariate correlation analyses were conducted with Spearman’s Rank Correlation analyses to inform multiple regression analyses of 19 dependent variables. Levels of diastolic blood pressure, estimated glomerular filtration rate (eGFR), LDL-c, visceral fat, oestrogen, FSH, and bioavailable testosterone differed between pre- and post- menopausal women. SHBG, oestrogen, bioavailable testosterone, DHEA-S, and FSH were significantly correlated with several cardiometabolic risk factors, anthropometric variables, and hormone levels. Gene methylation did not differ between menopause stages, and no association of gene methylation with CMD risk factors or hormone levels were noted suggesting that DNA methylation of sex hormone regulatory genes is unlikely to be a mechanism that modulates gene expression during the menopause transition in this cohort.