Erythrocyte odd-chain fatty acids and the risk of cardiometabolic diseases: a prospective study and updated meta-analysis

Aim To determine dietary sources of odd-chain fatty acids (OCFAs) in Asians and their associations with cardiometabolic diseases (CMDs) and to compare these associations with other populations. Methods Erythrocyte fatty acids were profiled in 8,185 subjects (38% men, mean age 58.1 years) participating in the 2nd resurvey of the China Kadoorie Biobank (CKB) in 2013-14 using gas chromatography. Correlations of pentadecanoic (15:0) and heptadecanoic (17:0) acids with dietary factors, assessed via food frequency questionnaires, were examined by Spearman correlations. During about 5-year follow-up, 950 incident CMD were recorded, including 387 ischemic heart disease (IHD), 127 diabetes, and 459 stroke. Cox regression yielded adjusted hazard ratios (HRs) for CMDs associated with levels of 15:0. These results were further meta-analyzed with 33 additional prospective studies, involving 112,193 participants. Results OCFAs were significantly correlated with intakes of dairy products, wheat and coarse grains, and fish/seafood in the CKB. Both 15:0 and 17:0 were inversely associated with incident IHD, with adjusted HRs of 0.72 (95% CI 0.59-0.89) and 0.69 (0.56-0.86) for top vs. bottom tertile, respectively. Levels of 17:0 were also inversely associated with incident diabetes (0.41 [0.27-0.62]) and total CMDs (0.85 [0.74-0.97]). In the updated meta-analysis, both 15:0 and 17:0 levels showed inverse associations with diabetes, with pooled relative risks of 0.74 (0.68-0.80) and 0.65 (0.61-0.71) per 10th-90th percentile range, respectively. 17:0 was also inversely associated with incident IHD (0.87 [0.77-0.97]). Conclusions Our findings supported favorable associations between OCFAs and CMDs among populations with varied dietary sources and intake levels, which merits future intervention studies.