DHA, DPA levels associated with lower ischaemic stroke risk
Higher circulating levels of docosahexaenoic acid (DHA) and docosapentaenoic acid (DPA) appear to be protective against incident atherothrombotic and cardioembolic strokes, respectively, according to a recent study.
Researchers measured data on baseline circulating phospholipid fatty acids from three separate US cohorts: CHS (Cardiovascular Health Study), NHS (Nurses’ Health Study) and HPFS (Health Professionals Follow-Up Study). They categorized the outcome of ischaemic strokes as atherothrombotic (large- and small-vessel infarctions) or cardioembolic.
During a median follow-up of 11.2 (CHS) and 8.3 years (pooled, NHS and HPFS), a total of 953 incident ischaemic strokes were reported. Of these, 408 were atherothrombotic, 256 were cardioembolic and 289 were of undetermined subtypes.
Multivariable Cox proportional hazards analysis found the risk of total ischaemic stroke to be lower with higher levels of DPA (highest vs lowest quartiles; pooled hazard ratio [HR], 0.74; 95 percent CI, 0.58 to 0.92) and DHA (pooled HR, 0.80; 0.64 to 1.00) but not eicosapentaenoic acid (pooled HR, 0.94; 0.77 to 1.19).
Specifically, higher DHA was protective against the risk of atherothrombotic stroke (HR, 0.53; 0.34 to 0.83), while higher DPA was associated with lower cardioembolic stroke risk (HR, 0.58; 0.37 to 0.92).
Researchers noted that the findings in each individual cohort were consistent with pooled results.
“[The] findings [also] suggest differential pathways of benefit for DHA, DPA and eicosapentaenoic acid,” they said.
The protective effect of DHA and DPA against ischaemic stroke has been previously investigated. Available evidence shows that accumulation of DHA in the brain may reduce neuroinflammation and activation of antiapoptotic pathways. [J Biol Chem 2003;278:43807–43817]
Meanwhile, DPA, along with other long-chain n-3 polyunsaturated fatty acids, has been reported to prevent arrhythmia and reduce the onset of atrial fibrillation by directly influencing atrial and ventricular myocyte electrophysiology, as well as modulations in autonomic tone. Another potential mechanism is an anti-inflammatory or antifibrotic effect. [J Am Coll Cardiol 2011;58:2047–2067]