Biomarker of dietary linoleic acid and risk for stroke: A systematic review and meta-analysis

Objective: Previous observational studiíes provided conflicting findings on the relationship between linoleic acid (LA) and the risk for stroke. The aim of this study was to evaluate the association of LA levels in blood or adipose tissue samples with risk for stroke.

Methods: PubMed, Web of Science, and Embase databases were searched until February 29, 2020 to identify eligible observational studies, including cohort studies, nested case-control studies, case-cohort studies, and case-control studies, reporting the association of LA with the risk for stroke and its subtypes. We pooled hazard ratio (HR) estimates with 95% confidence intervals (CIs) and conducted heterogeneity test. Sensitivity analysis and publication bias test were also carried out.

Results: Twelve studies from 11 observational articles involving 47 836 individuals were included in the meta-analysis. We observed an inverse association between biomarkers of dietary LA and risk for total stroke (HR, 0.88; 95% CI, 0.83-0.94; P < 0.001). Meta-regression analysis suggested that ethnicity (P = 0.029) and study design (P = 0.049) contributed to between-study heterogeneity. Subgroup analysis showed that the association was statistically significant among studies conducted in white (P < 0.001) and Asian (P = 0.032) populations, and those with cohort (P = 0.001) and case-cohort design (P = 0.007). Moreover, we found that higher LA levels were associated with a reduced risk for ischemic stroke (HR, 0.87; 95% CI, 0.80-0.95; P = 0.001), although no statistically significant association was found between LA levels and the risk for hemorrhagic stroke.

Conclusions: The present study supported an inverse association of LA levels with the risk for stroke, particularly ischemic stroke. Racial disparity exists in the association between LA and the risk for stroke, which deserves further studies.

Keywords: Hemorrhagic stroke; Ischemic stroke; Linoleic acid; Meta-analysis; Stroke.