Poor Prepregnancy Cardiovascular Health tied to Midlife Heart Risk, Independent of Gestational Diabetes: JAMA
Researchers have discovered in a new cohort study that less favorable prepregnancy cardiovascular health (CVH) is associated with subclinical cardiovascular disease (CVD) in midlife. While gestational diabetes (GD) played a minor mediating role, the findings suggest that GD is more a marker of poor prepregnancy CVH than a direct cause. The study published in JAMA highlights the importance of improving cardiovascular health early in life, well before pregnancy. The study was conducted by Natalie A. and fellow researchers.
The study aimed to examine whether gestational diabetes acts as a mediator (a causal link) or a marker (a signal) of the relationship between prepregnancy CVH and later cardiovascular risks. It was performed in the context of the CARDIA (Coronary Artery Risk Development in Young Adults) study, a long-term, multi-center, population-based cohort study that has followed a diverse cohort of young adults in four US cities since 1985. The researchers identified a cohort of 1,052 Black and White women with at least one singleton birth between baseline and 15-year follow-up, complete data on their CVH prior to pregnancy, and data on coronary artery calcium (CAC) assessed between 15 and 25 years later. All patients had no history of diabetes before pregnancy.
The exposure of interest was cardiovascular health pre-pregnancy, which was quantified using the American Heart Association's Life's Simple 7 scoring system, which incorporates aspects such as diet, physical activity, blood pressure, and cholesterol. The scores range from 0 to 14, with higher scores reflecting improved heart health. Researchers segregated participants into two categories: low to moderate CVH (scores 0–10) and high CVH (scores 11–14). The primary outcome was the presence of coronary artery calcium (CAC), a subclinical atherosclerosis marker, identified by CT scans between the 15–25-year follow-up period. The analysis controlled for age, race, education, and parity, and was supplemented with mediation modeling to calculate the proportion of the CVH-CAC relationship that was explained by gestational diabetes.
Results
Participants' average age was 28.6 years, and almost half (47.6%) were Black and 52.4% were White.
Women with a lower CVH prior to pregnancy had higher rates of GD (8.8%) than those with high CVH (6.3%).
They were also at greater odds of exhibiting CAC in midlife: 28.2% with low/moderate CVH exhibited CAC compared with 19.2% with high CVH.
The adjusted odds ratio for the development of GD in women with poor CVH was 1.8 (95% CI: 1.1–3.0), and for the development of CAC, 1.7 (95% CI: 1.2–2.5).
Nonetheless, GD accounted for only 6% of the augmented risk of CAC (95% CI: 0%–22%), indicating that it is not the principal cause of midlife CVD in this population.
Overall, this large, long-term study demonstrates that poor prepregnancy cardiovascular health is highly predictive of the presence of subclinical heart disease in later life, though not substantially mediated through gestational diabetes.
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