Introduction: It is unclear if maternal overnutrition during pregnancy increases risk of offspring heart disease. This study aimed to examine the relationship between maternal pre-pregnancy body mass index (BMI) and offspring systolic blood pressure (SBP) at 18 years old.
Methods: Multivariate regression and causal mediation analysis were performed within 3700 mother – offspring pairs from a prospective birth cohort. The main exposure was maternal pre-pregnancy BMI categorized as healthy weight, overweight, or obese for regression and treated as continuous for causal mediation analysis. The main outcome was offspring BP considered as elevated-normal BP (SBP 130/>80mmHg) at 18 years. Age-standardized BMI Z-scores and latent class growth analysis (LCGA) were used to quantify the mediating factor of offspring BMIZ trajectories between 7 and 18 years. Analyses were adjusted for social class, pre-eclampsia, sex, and maternal tobacco use during pregnancy.
Results: The odds of elevated BP (aOR: 1.6; 95% CI: 1.1-2.3) and hypertension (aOR: 2.1; 95% CI: 1.4-3.1) were higher in offspring from women that were obese prior to pregnancy compared to those that were healthy weight. LCGA identified five distinct offspring BMIZ trajectories. SBP (125 ± 12 vs 117 ± 10 mmHg, p < 0.001) and the odds of hypertension (aOR: 3.8; 95% CI: 2.8-5.1) at 18 years were significantly higher in offspring with sustained high BMIZ trajectory compared to sustained low normal. Casual mediation analysis revealed that maternal BMI directly (OR: 1.14; 95% CI: 1.03-1.25) and indirectly through offspring BMIZ trajectories (OR: 1.12; 95% CI: 1.08-1.15) increased offspring SBP at 18 years of age.
Conclusion: Maternal obesity prior to pregnancy is associated with increased risk of hypertension in offspring at 18 years of age, partly mediated by an elevated BMIZ score trajectory throughout childhood and adolescence.
Brenden Dufault– Biostatistician | Data Sciences Platform, George & Fay Yee Centre for Healthcare Innovation
Allison Dart– Pediatric Nephrologist, Clinical Researcher, Department of Pediatrics and Child Health, Rady Faculty of Health Sciences, University of Manitoba
Meghan Azad– Associate Professor, 1Children’s Hospital Research Institute of Manitoba (CHRIM), 4Pediatrics and Child Health, 5Developmental Origins of Chronic Diseases in Children Network (DEVOTION), 6Biology of Breathing Research Theme, and 7University of Manitoba.
Jonathan McGavock– Associate Professor, University of Manitoba