Omega-3 Index as a Risk Factor of Ischemic and Haemorrhagic Stroke: A Pilot Case-Control Study

Abstract

Bacground& Aim: Diet may have effects on stroke. Previous studies suggested that fish consumption and blood level of omega-3 fatty acids such as eicosapentaenoic acid (EPA; C20:5n3) and docosahexaenoic acid (DHA; C22:6n3) negatively correlated with ischemic stroke, but the relation to the risk of haemorrhagic stroke remains uncertain. This study investigated the effect of Omega-3 Index (EPA + DHA in red blood cell, RBC) on hemorrhagic and ischemic stroke, and association between Omega-3 Index and other traditional risk factors of stroke. Method: Hemorrhagic (n=26) and ischemic stroke (n=33) cases, and controls (n=20) were included in the present case-control study. Dietary intake was assessed using a semi-quantitative food frequency questionnaire and Omega-3 Index was measured by GC. Lipid profile, blood pressure (BP), HbA1c, hemoglobin (Hb), aspartate aminotransferase (AST), alanine aminotransferase (ALT), calcium (Ca), and C-reactive protein (CRP) were also measured by auto-analyzers. Results: Body mass index did not significantly differ between groups. Age was significantly higher in ischemic stroke groups than control group (60.70±1.94 vs. 49.25±3.27), but age of haemorrhagic stroke group (56.38±2.82) did not different. Omega-3 Index (10.22±0.64 vs. 8.11±0.49 and 8.50±0.63%) was significantly higher in control group than ischemic and haemorrhagic stroke groups. Total n-3 fatty acids (13.30±0.81 vs. 10.13±0.89%), C22:5n3 (1.71±0.16 vs. 1.12±0.11%), C22:5n6 (2.58±0.16 vs. 1.93±0.21%), C22:6n3 (DHA; 8.51±0.52 vs. 6.38±0.54%) and total polyunsaturated fatty acids in RBC were significantly higher in control group than ischemic stroke group, but total n-3 fatty acids, C22:5n3, C22:5n6, C22:6n3 and total polyunsaturated fatty acids of haemorrhagic stroke group did not different. C16:0 (22.38±0.67 and 23.27±0.51 vs. 26.79±1.04%), C18:0 (17.58±0.39 and 16.91±0.52 vs. 21.01±0.82%) and total saturated fatty acids (42.77±0.69 and 41.99±0.91 vs. 49.63±1.86%) in RBC were significantly lower in control and haemorrhagic stroke groups than ischemic stroke group. Systolic BP was significantly higher in haemorrhagic and ischemic stroke groups than control (136.25±5.65 and 135.33±2.98 vs. 116.25±3.64 mmHg). Diastolic BP was higher in ischemic stroke than control group (85.00±1.84 vs. 75.63±2.23 mmHg) but diastolic BP of haemorrhagic stroke group (83.75±5.65 mmHg) did not different between other groups. Hb was significantly higher in ischemic stroke than haemorrhagic stroke group (14.41±0.41 vs. 12.64±0.53 g/dl). Blood Ca was significantly higher in control than ischemic and haemorrhagic stroke group (9.05±0.14 vs. 8.53±0.07 and 8.40±0.16 mg/dl). Blood glucose was higher in haemorrhagic stroke than control group (125.00±12.59 vs. 92.09±4.03 mg/dl), but blood glucose of ischemic stroke group (103.48±2.96 mg/dl) did not different between other groups. HbA1c, lipid profile, AST, AST, and CRP did not significantly differ between groups. Control consumed significantly more brown rice (15.55±3.04 vs. 6.91±1.54 servings/week), bean (9.15±0.84 vs. 5.48±0.76 servings/week) and fruits such as tomato, watermelon and strawberry (4.36±0.67 vs. 2.16±0.39 servings/week) than haemorrhagic stroke groups. Control consumed significantly more bean paste soup (4.65±0.52 vs. 2.16±0.39 and 3.08±0.40 serving/week) than haemorrhagic and ischemic stroke groups. Fishand seafood intake did not significantly differ between groups. In addition, individual nutrients, alcohol intake, smoking and exercise did not significantly differ among groups. Conclusion: Omega-3 index was higher in control group than haemorrhagic and ischemic stroke groups, suggesting that n-3 fatty acids may have beneficial effect on haemorrhagic and ischemic strokes. Consumption of brown rice, fruit, bean, and bean paste soup may also have beneficial effect on stroke.