Prepregnancy CV Health Portends Midlife Risks: CARDIA Analysis

Optimizing CV risk factors before pregnancy appears most important for preventing heart disease decades later.

Prepregnancy CV Health Portends Midlife Risks: CARDIA Analysis

Poor cardiovascular health (CVH) prior to pregnancy may be more of a marker of risk for subclinical atherosclerosis in midlife than adverse events occurring during pregnancy, such as gestational diabetes, according to an analysis of US women followed for decades.

Among more than 1,000 women in the long-running CARDIA study, those with poor prepregnancy CVH, as quantified using the American Heart Association (AHA)’s Life’s Simple 7 score (now Life’s Essential 8), were 1.7 times more likely to have evidence of subclinical CVD in the form of a coronary artery calcium (CAC) score > 0 at 20 years postpartum than those with good prepregnancy CVH.

“When we put everything in the model, only about 6% of coronary artery calcium was caused by gestational diabetes,” said Natalie A. Cameron, MH, MPH (Northwestern University Feinberg School of Medicine, Chicago, IL). “What this really emphasizes to us is that we need to work on improving health before pregnancy, both to prevent gestational diabetes and also help prevent heart disease later in life.”

A recent scientific statement from the American Heart Association (AHA) highlighted several adverse pregnancy outcomes with known links to CVD, including gestational diabetes. According to Cameron and colleagues, it’s been unclear just how much gestational diabetes plays into long-term CV risk.

“There [are] two hypotheses about how adverse pregnancy outcomes are associated with heart disease. One is as a causal pathway that kicks something off that then leads to metabolic changes or cardiovascular changes during pregnancy that cause heart disease later in life,” Cameron told TCTMD. “The other hypothesis lies in the idea of pregnancy as a stress test. If you have heart disease risk factors before pregnancy like overweight, obesity, prediabetes, high cholesterol, or high blood pressure, you are more likely to ‘fail’ the stress test [and] to develop an adverse pregnancy outcome. That underlying risk rather than the gestational diabetes itself is the cause.”

One of the main take-aways from this analysis, Cameron and colleagues say, is that pregnancy does appear to unmask preexisting CVD risk.

They say data are now needed to understand postpartum CVH, including changes in risk components and the impact of lactation, in order to better inform the timing and targeting of appropriate prevention strategies.

CVH, Gestational Diabetes, and CAC

For the study, published this week in JAMA Cardiology, the researchers examined data on 1,052 women (mean age 28.6 years; 47.6% Black) enrolled in CARDIA beginning in 1985. Self-reported and in-office data were used to categorize prepregnancy CVH as either high (11-14) or low/moderate (0-10). CAC was measured at 15, 20, and 25 years.

Individuals with low/moderate prepregnancy CVH were more likely than those with high prepregnancy CVH to identify as non-Hispanic Black, have less than a high school education, and have a history of a previous live birth.

Gestational diabetes occurred in 7.5% overall, but was more common in  those with low/moderate compared with high scores (8.8% vs 6.3%; adjusted OR 1.8; 95% CI 1.1-3.0).

Having gestational diabetes correlated with a higher incidence of any CAC > 0 (25.3% vs 15.1%), shorter time to CAC (11.7 vs 13.8 years), and higher mean CAC levels (6.5 vs 4.8 Hounsfield units) when compared with not having gestational diabetes.

Similarly, those with low/moderate CVH scores also were more likely than those with high scores to develop CAC > 0 at 20 years (28.2% vs 19.2%). After adjustment for age, race, education, and parity, having low/moderate prepregnancy CVH was associated with higher levels of incident CAC (OR 1.74; 95% CI 1.23-2.50), shorter time to CAC (time ratio 0.84; 95% CI 0.74-0.94), and higher CAC levels (ratio of geometric means 1.53; 95% CI 1.23-1.92) than having high prepregnancy CVH scores.

In addition to the small association between prepregnancy CVH and incident CAC mediated by gestational diabetes, the investigators also saw no evidence that gestational diabetes mediated the association between prepregnancy CVH and the time to CAC.

One limitation of the study lies in its generalizability, Cameron noted, since CARDIA first recruited participants about 40 years ago and only included those identifying as Black or white, leaving other racial and ethnic groups unrepresented.

Given emerging evidence that children born to mothers with cardiometabolic risk factors are themselves at risk for CV risk factors, such as higher blood pressure during early childhood, Cameron and colleagues say an additional message of their study is that improving prepregnancy CVH could have important implications for intergenerational CVD.

Sources
Disclosures
  • Cameron reports no relevant conflicts of interest.

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