Plasma ω-3 and ω-6 fatty acids in thyroid diseases

The incidences of nodular goiter (NG), thyroid adenoma (TA), and thyroid cancer (TC) are increasing rapidly; however, the etiologies of these diseases remain unclear. The present study aimed to evaluate the differences in plasma fatty acids among these three thyroid diseases to facilitate etiological research. Four ω-3 and seven ω-6 polyunsaturated fatty acids were measured from 97 TC, 14 TA and 11 NG patient plasma samples with gas chromatography-flame ionization detector. Fatty acids levels were expressed as the percentage of each fatty acid out of the total fatty acids evaluated. The present study identified that the level of 22:6n-3 [median, interquartile range (IQR)] was significantly increased in TA (5.2%, 4.3-6.4%) compared with NG (3.6%, 3.1-4.6%) and TC patients (4.2%, 3.2-4.8%). Though not statistically significant, the levels of 20:5n-3 and 22:5n-3 demonstrated a similar pattern. The level of 22:4n-6 expressed (median, IQR) was significantly increased in NG patients (0.21%, 0.18-0.26%) compared with TA (0.16%, 0.15-0.18%) and TC (0.17%, 0.14-0.22%) patients. Furthermore the fatty acids 18:3n-6, 20:2n-6, 20:3n-6, 20:4:6, and 22:5n-6 demonstrated a similar but statistically insignificant pattern. This suggests that different fatty acids exhibit various etiological roles in NG, TA and TC and warrant further study.