Association between blood polyunsaturated fatty acid levels and depressive symptoms in breast cancer survivors

In contrast to the cumulative evidence suggesting the inverse association of n-3 polyunsaturated fatty acids (PUFAs) with depression, few studies have examined the association of n-6 PUFAs with depression. In particular, no study has examined the relationship between n-6 PUFAs and depression in cancer patients. Thus, we conducted this cross-sectional study to comprehensively examine the association of n-3 and n-6 PUFAs with depressive symptoms in breast cancer survivors. Adults who had been diagnosed with invasive breast cancer and were not undergoing chemotherapy were enrolled. Blood PUFA composition was determined using capillary blood. Depressive symptoms were assessed using the Hospital Anxiety and Depression Scale (HADS). Among 126 participants, the mean age (standard deviation) was 58 (11) years and 47% had stage I cancer. Multiple regression analysis controlling for possible confounders revealed that the level of total n-6 PUFAs and linoleic acid was significantly associated with the HADS total score (beta = 0.175, p = 0.046 for total n-6 PUFAs; beta = 0.174, p = 0.048 for LA). No significant associations were found for other PUFAs. These findings provide the first evidence suggesting that a higher blood level of total n-6 PUFAs and linoleic acid is significantly associated with higher depressive symptoms among breast cancer survivors. Further studies should examine the positive effects of a reduction in n-6 PUFAs on depressive symptoms in breast cancer survivors using prospective studies, including randomized control trials.