Erythrocyte n-3 fatty acids and metabolic syndrome in middle-aged and older Chinese.

CONTEXT Few studies examined associations of circulating n-3 fatty acid levels with metabolic syndrome (MetS) among Chinese populations who have low consumption of these fatty acids and high risk of developing MetS. OBJECTIVE The objective of the study was to determine associations between erythrocyte n-3 fatty acids and MetS as well as its components among middle-aged and older Chinese men and women. DESIGN AND PARTICIPANTS Erythrocyte levels of docosahexaenoic acid (DHA), docosapentaenoic acid, eicosapentaenoic acid, and α-linolenic acid (ALA) were measured by gas chromatography among 2754 participants aged 50-70 yr living in Beijing and Shanghai. MetS was defined using the updated National Cholesterol Education Program Adult Treatment Panel III criteria for Asian-Americans. RESULTS After multivariable adjustment, higher levels of DHA, but neither eicosapentaenoic acid nor docosapentaenoic acid, were associated with lower odds of MetS as well as elevated blood pressure and triglycerides. Comparing extreme quartiles of DHA, odds ratios (95% confidence interval) were 0.75 (0.55, 1.01; P for trend = 0.04) for MetS; 0.70 (0.53, 0.92; P for trend = 0.01) for elevated blood pressure; and 0.64 (0.48, 0.87; P for trend = 0.005) for elevated triglycerides. In contrast, ALA concentrations were positively associated with MetS odds (odds ratio 4.06; 95% confidence interval 2.85, 5.80; P for trend <0.001). CONCLUSIONS Higher concentrations of erythrocyte DHA were associated with lower odds of MetS, whereas higher concentrations of ALA were associated with increased odds among middle-aged and older Chinese. These findings warrant replication in other populations.