It’s another on the list of long-term health implications, but it’s reassuringly rare.
Having preeclampsia more than doubles the risk of developing early-onset dementia, according to a recent French study surveying nearly 20 million women.
The risk is multiplied by more than four if preeclampsia occurs before 34 weeks’ gestation, and closer to five when it comes on top of chronic hypertension. The absolute risk is still under 0.01%.
“The results suggested a dose-dependent association, with higher HRs for early-onset preeclampsia and superimposed preeclampsia,” the authors write.
The study canvassed records for everyone who gave birth in France after 22 weeks’ gestation from 2010 to 2018 – around 19.7 million people.
During follow-up (until the end of 2021 for those aged 30 and over and without a history of dementia) 128 developed dementia. The data showed no significant raised risk for severe preeclampsia, but the authors noted that could be due to the small numbers in the subgroup.
Slightly older age (36.4 years vs 34.6), being a smoker (15% vs 9%), having diabetes (2.3% vs 0.7%) and social deprivation (13% vs 12%) had a greater association with developing early-onset dementia (defined as under the age of 65).
This newly identified risk increase for early onset dementia is in addition to recent research showing that hypertensive disorders during pregnancy triple the risk of late-onset vascular dementia. It adds to the body of research already incorporated into guidelines showing that a hypertensive disorder during pregnancy triples the risk of subsequent hypertension, more than doubles the risk of coronary heart disease, quadruples the risk of heart failure, and roughly doubles the risk of cardiovascular disease death and stroke.
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“Now that we know, what are we to do with this new knowledge? Should individuals with a past episode of preeclampsia be concerned about developing young-onset dementia before their child has even reached secondary school?” asks a commentary in the same journal.
The absolute risk of developing young onset dementia in the general community at the same age as those in the study (between 30 and 45) is only 1.0-3.8 per 100,000 (0.001-0.0038%). That’s compared to 6.5 cases per 100,000 in the study, the commentary notes.
“Hence, individuals who have had preeclampsia should be reassured that young-onset dementia remains a very rare condition. Their absolute risk increases only imperceptibly … Instead, individuals who have been affected by preeclampsia in a prior pregnancy might instead focus on reducing their risk of developing the many chronic health ailments that are far more common,” the commentators suggest.
“Although it is yet to be proven in clinical trials, it is plausible that after an episode of preeclampsia, adopting a healthy lifestyle may improve vascular health and reduce the risk of many serious cardiovascular conditions. Furthermore, if the pathology causing an increased dementia risk is also mediated through poor vascular health, a healthy lifestyle may also mitigate this risk, too. If so, then the message is clear – healthy diet, regular exercise, and engaging with primary health care physicians may reduce the risk of all these conditions associated with preeclampsia in one fell swoop.”
