http://www.medpagetoday.com/Cardiology/Strokes/31434?utm_source=cardiodaily&utm_medium=email&utm_content=aha&utm_campaign=03-01-12&eun=gd3r&userid=424561&email=oc1dean@yahoo.com&mu_id=
High trans fat intake may boost stroke risk for postmenopausal women, but aspirin appears to bring it back down, according to an observational study.
Women who ate the most trans fats were 39% more likely to have an ischemic stroke compared with those who had the least in their diet (P=0.048 for trend) Ka He, MD, ScD, MPH, of the University of North Carolina at Chapel Hill's School of Global Public Health, and colleagues found.
Aspirin use altered the link, though, with no effect of trans fat intake for women taking it (P=0.43 for trend) but a 66% elevated ischemic stroke risk for non-aspirin users with the highest trans fat consumption (P<0.01 for trend), they reported online in the Annals of Neurology.
"Our results highlight the importance of limiting the amount of dietary trans fat intake and using aspirin for primary ischemic stroke prevention among women, specifically postmenopausal women who have elevated risk of ischemic stroke," the group wrote.
Trans fats, which are typically found in processed food from partial hydrogenation of vegetable oils, are thought to raise heart disease risk by boosting cholesterol, inflammation, and endothelial dysfunction.
But the link between fats and stroke has been less straightforward, and two large studies of healthcare professionals found no association of trans fats with ischemic stroke.
Because those studies included relatively few strokes, He's group analyzed the more than 1,000 incident ischemic strokes in the prospective Women's Health Initiative Observational Study according to food frequency questionnaires filled out by the 87,025 generally healthy postmenopausal women who participated.
Total fat intake, cholesterol consumption, and other types of fats aside from trans fat showed no association with ischemic stroke.
For trans fat, the hazard ratios for ischemic stroke adjusted for age and ethnicity rose with trans fat intake compared with the lowest intake quintile that averaged 2.2 g per day (P=0.0002 for trend):
- 1.22 for the quintile that consumed an average 2.3 g per day (95% CI 0.99 to 1.51)
- 1.37 for the quintile that got an average 2.6 g per day (95% CI 1.11 to 1.68)
- 1.33 for the quintile that averaged 3.4 g per day (95% CI 1.09 to 1.64)
- 1.49 for the highest intake group who averaged 6.1 g per day (95% CI 1.22 to 1.82)
The association attenuated slightly but remained significant with further adjustment for factors such as fruit and vegetable and fiber in the diet, as well as socioeconomic factors, use of hormone replacement therapy, smoking and medical history, and use of medications including aspirin.
The impact of dietary trans fat was modified by aspirin use, which was consistent across all three types of trans fat isomers (P=0.04 to 0.002 for interaction), though not by use of statin medication or menopausal hormone therapy or alcohol intake.
"Increased platelet response to an agonist and inhibition after aspirin intake may at least in part explain the attenuated association between trans fat intake and ischemic stroke among aspirin users in this cohort," the researchers suggested.
Aspirin may make a difference in this population in particular because of the higher platelet reactivity among women and greater platelet aggregability with older age, they noted.
The group cautioned that they may have been underpowered to show an effect of statins in modifying the association with trans fat, but noted that fatty acid intake was a key measure in the food frequency questionnaires used.
Confounding was possible but unlikely, as the results remained consistent through several sensitivity analyses, they added.
Impressive post. Thanks for this.
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