Plasma Fatty Acids, Not Dietary Fatty Acids, Associated with Obesity in Four Ethnic Minority Groups Unique to Southwest China: A Cross-Sectional Study

BACKGROUND: Dietary fatty acids (DFAs) and plasma fatty acids (PFAs) are linked to obesity. However, whether this association exists among ethnic minorities remains lacking. The present cross-sectional study was designed to investigate the correlation between DFAs, PFAs and obesity in four ethnic minority groups to Southwest China. METHODS: A total of 166 obese people, and 166 normal-BMI subjects matched based on their age-, sex-, and ethnicity- were recruited from four different ethnic minority groups. DFAs were obtained through food frequency questionnaires. PFAs were assayed by GC/MS method. Binary and multiple regression analyses were performed to evaluate the correlation among DFAs, PFAs and obesity. Canonical correlation analysis (CCA) was conducted to assess the relationship between DFAs and PFAs. RESULTS: FAs were found to be highest in the Naxi people and lowest in the Hani people. Multiple logistic regression analysis revealed that plasma C16:0 (OR = 1.310; 95% CI, 1.028–1.669) in the Hani people; plasma C20:3 n-6 (OR = 6.250; 95% CI, 1.224–31.927) and dietary C20:1 (OR = 9.231; 95% CI, 1.253–68.016) in the Wa people; plasma C18:0 (OR = 0.788; 95% CI, 0.681–0.912) in the Naxi people were seen to be independent predictive factors for obesity. CCA showed that DFAs were positively correlated with PFAs in the Naxi (r: 0.676; P < 0.05) and Bulang people (r: 0.897; P < 0.05), but there was no correlation in the Hani and Wa people. CONCLUSION: In this study, PFAs but not DFAs were independently associated with obesity, and different among the four ethnic minorities.