This study investigated the associations of twin pregnancies with early-onset (EO)- and late-onset (LO)-hypertensive disorders of pregnancy (HDP). Totally, 86,717 pregnant women were included in a prospective birth cohort study. The associations of dichorionic diamniotic (DD)- and monochorionic diamniotic (MD)-twin pregnancies with EO-HDP (Diagnosed from 20 to <34 weeks of gestation) and LO-HDP (Diagnosed at ≥34 weeks of gestation) were analyzed using a multinomial logistic regression model. Compared with singleton pregnancies, both DD- and MD-twin pregnancies had significantly higher odds for EO- and LO-HDP. The adjusted odds ratios (aORs) for EO-HDP were 2.05 (95% confidence interval [Cl]: 1.51-2.78) in DD-twin pregnancies and 2.80 (95% Cl: 2.01-3.90) in MD-twin pregnancies, respectively. Also, the aORs for LO-HDP were 1.32 (95% CI: 1.03-1.69) in DD-twin pregnancies and 1.64 (95% Cl: 1.24-2.17) in MD-twin pregnancies, respectively. Although no statistically significant differences were observed, MD-twin pregnancies tended to have higher odds for both EO- and LO-onset HDP compared with DD-twin pregnancies. In conclusion, both DD- and MD-twin pregnancies are risk factors for the development of EO- and LO-HDP. We showed that both dichorionic diamniotic and monochorionic diamniotic twin pregnancies are risk factors for the development of early-onset and late-onset hypertensive disorders of pregnancy.
Chronological age is a well-established risk factor for Hypertension (HTN), yet while biological ageing markers such as epigenetic age acceleration (EAA), have been associated with HTN, findings are inconsistent. This study aimed to conduct a systematic review and meta-analysis to evaluate the association between EAA, HTN and blood pressure (BP) to provide an understanding of the role of EAA in HTN development and progression. Six databases were searched, and studies which reported associations between DNA and HTN, and/or BP were included. Functional enrichment analysis was conducted using DAVID and STRING to elucidate underlying molecular pathways. From 4334 studies, 165 met the inclusion criteria. Qualitative analysis indicated that 17.0% of studies reporting global methylation and 49.1% of studies reporting gene-specific methylation demonstrated significant associations with HTN and/or BP. A random effects meta-analysis of 16,136 participants from 8 studies using three epigenetic clock algorithms demonstrated that HTN was associated with increased EAA (β: 0.29, 95%Cl: 0.15-0.43; P < 0.0001). All three individual epigenetic clocks demonstrated a positive association between clinically measured HTN and EAA (Horvath β: 0.33, 95%Cl: 0.08-0.58, P = 0.010; Hannum β: 0.64, 95%Cl: 0.09-1.20; PhenoAge β: 1.21, 95%Cl: 0.56-1.86), whereas this relationship was not clear when using self-reported HTN. This study is the first to systematically demonstrate that HTN is associated with EAA. We recommend the use of clinically measured over self-reported HTN in appropriately powered studies of epigenetic age to obtain an accurate understanding of BP regulation/HTN on the epigenome, supporting pathways to translation and development of novel therapeutic targets for HTN.

