Objective Studies have shown that hypertensive disorders of pregnancy (HDP) are associated with both postpartum retinal microvascular changes and cardiovascular (CV) risks. However, the underlying mechanism of HDP transitioning to microvascular and macrovascular changes remains unknown, due to the interaction between microvasculature and CV risks. In this study, we examined whether associations between antenatal systolic blood pressure (SBP) and postpartum retinal arteriolar changes are independent of postpartum CV risks.
Methods We included 276 Singaporean mothers attending both baseline index pregnancy (2009–2010) and 5-year postpartum follow-up visits (2014–2015). We measured SBP at baseline. At follow-up, we assessed retinal microvascular structure and function with retinal photography and dynamic vessel analyser, together with CV risks using a validated 2008 Framingham Risk Score (FRS). We performed a traditional four-step mediation analysis using linear regression by adjusting for a series of baseline characteristics: age, ethnicity, college degree, prepregnancy body mass index and gestational diabetes mellitus diagnosis at baseline.
Results We found that each 10 mm Hg increase in baseline SBP was associated with reduced arteriolar calibre (−1.3 µm; 95% CI −3.0 to 0.2) and fractal dimension (−0.4 degrees of freedom (df); −1.0 to 0.2), and significantly with increased arteriolar constriction (0.5%; 0.001 to 1.0) at 5-year postpartum. Even though baseline SBP was associated with postpartum FRS, the latter was not associated with any retinal arteriolar measures. Therefore, no further mediation analysis was required.
Conclusion Our study suggested that elevated SBP during pregnancy was associated with suboptimal retinal arteriolar structure and function independent of postpartum CV risks.
- public health
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Contributors We declare here that all authors have read and approved the submission of the manuscript; the manuscript has not been published and is not being considered for publication elsewhere, in whole or in part, in any language. All authors have contributed significantly and are in agreement with the content of the manuscript. RS conducted the literature review, drafted the manuscript and conducted data analysis and interpretation. IMA supervised the data analysis, helped interpret the data and edited the manuscript. YSC designed the study and edited the manuscript. TYW supervised the data analysis and edited the manuscript. L-JL designed the study, directed its implementation, designed the study’s analytical strategy, reviewed and edited the manuscript.
Funding This study was funded by Singapore National Medical Council Transition Award, grant number: NMRC TA/0027/2014, NMRC/CG/C008A/2017_KKH and Singapore National Medical Council, grant number: NMRC/CNIG/1114/2013.
Competing interests All authors have completed the ICMJE uniform disclosure form at www.icmje.org/coi_disclosure.pdf and declare: this study is funded by the Singapore National Medical Council (NMRC/CNIG/1114/2013), L-JL is funded by a Singapore National Medical Council Transition Award (NMRC/TA/ 0027/2014). The GUSTO cohort, under the Translational Clinical Research (TCR) Flagship Program on Developmental Pathways to Metabolic Disease, is funded by the Singapore National Research Foundation (NRF) and administered by the Singapore National Medical Research Council (NMRC/TCR/004-NUS/2008). The authors declare no financial relationships with any organisations that might have an interest in the submitted work in the previous three years; no other relationships or activities that could appear to have influenced the submitted work.
Patient consent for publication Not required.
Ethics approval We obtained approval from the SingHealth Centralised Institutional Review Board and the National Health Group’s Domain Specific Review Board. We conducted the study according to the tenets of the Declaration of Helsinki and obtained informed written consent from each participant at the 5-year follow-up visit.
Provenance and peer review Not commissioned; externally peer reviewed.
Data availability statement Data are available upon request.
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