<b>OBJECTIVE</b>
<p>To evaluate
associations between gestational diabetes mellitus (GDM) and various incident
cardiovascular disease (CVD) endpoints, considering the effects of mediating
role of type 2 diabetes and shared environmental/familial
factors.</p>
<p><b>RESEARCH DESIGN AND METHODS</b></p>
<p>This
population-based cohort study included 1002486 parous women in Denmark during
1978-2016. We used Cox regression to (i) examine the associations of GDM with overall
and type-specific CVDs using full-cohort and sibling-matched analysis; (ii)
quantify the impact of type 2 diabetes after GDM
using mediation analysis; and (iii) assess whether these associations were modified
by pre-pregnancy obesity or maternal history of CVD.</p>
<p><b>RESULTS</b></p>
<p>Women with a history of GDM had a 40% increased overall CVD risk (hazard
ratio [HR]: 1.40, 95% confidence
interval [CI]: 1.35-1.45). Sibling-matched analyses yielded
similar results(HR, 1.44; 95%CI, 1.28-1.62). Proportion of association between GDM and overall CVD explained
by subsequent type 2 diabetes was 23.3%(15.4%-32.8%).
We observed increased risks of specific CVDs, including
65% increased stroke risk and more than two-fold risks for myocardial
infarction, heart failure, and peripheral artery disease. The elevated overall risks were more
pronounced among women with GDM and pre-pregnancy obesity or maternal history of CVD. </p>
<p><b>CONCLUSIONS</b></p>
<p>A history of GDM was associated with increased risks
of overall and specific CVDs. Increased risks were partly explained by
subsequent type 2 diabetes and the need to identify
other pathways remains important. Continuous monitoring of women with a history
of GDM, especially those with pre-pregnancy obesity or maternal history of CVD,
may provide better opportunities to reduce their cardiovascular risk.</p>