BACKGROUND Temporality of the association of low omega-3 polyunsaturated fatty acid (n-3 PUFA) plasma levels with depression remains questionable. To determine the underlying nature of these associations, this study examined the bidirectional longitudinal associations of n-3 PUFA plasma levels with (presence, onset and course of) depressive disorders and symptoms. METHODS Baseline (n = 2912, 28.6% with current depressive disorder) and 6-year follow-up data (n = 1966, 13.0% with current depressive disorder) of the Netherlands Study of Depression and Anxiety (NESDA) were used. Depression diagnoses and symptoms were based on psychiatric interviews and self-report questionnaires. N-3 PUFA levels (ratio of total fatty acids (mmol%)), were assessed using nuclear magnetic resonance. RESULTS Using two waves of data, n-3 PUFA levels were lower among depressed persons, as compared to healthy controls (Beta = -0.047, SE = 0.011, p < .001). Nevertheless, baseline n-3 PUFA levels were not consistently associated with subsequent change in depressive symptoms, onset or remission of depressive disorders over 6 years. Furthermore, the difference in n-3 PUFA levels detected at baseline between depressed and non-depressed participants tended to dissipate over 6 years (depression-by-time estimate: p = .011). Finally, subjects depressed both at baseline and at 6-year follow up had consistently lower n-3 PUFA levels over the entire follow-up as compared to those who had never been depressed. Change in depressive disorders across waves was not consistently accompanied by change in n-3 PUFA levels over time. LIMITATIONS No data on intermediate time points and EPA levels were available. CONCLUSIONS Despite significant cross-sectional associations between n-3 PUFA plasma levels and depressive disorders and severity, this 6-year longitudinal study could not confirm an uni- or bidirectional association over time. The association between depression and n-3 PUFA plasma levels is unlikely to be causal.

中文翻译：

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ω-3多不饱和脂肪酸血浆水平与抑郁症的双向纵向关联。

背景低omega-3多不饱和脂肪酸（n-3 PUFA）血浆水平与抑郁症的关联的暂时性仍然值得怀疑。为了确定这些关联的内在本质，本研究检查了n-3 PUFA血浆水平与抑郁症（的存在，发作和过程）的双向纵向关联。方法使用荷兰抑郁与焦虑研究（NESDA）的基线（n = 2912，当前抑郁症患病率为28.6％）和6年随访数据（n = 1966，当前抑郁症患病率为13.0％）。抑郁症的诊断和症状基于精神病学访谈和自我报告调查表。使用核磁共振评估N-3 PUFA水平（总脂肪酸比（mmol％））。结果使用两波数据，与健康对照相比，抑郁者的n-3 PUFA水平较低（β= -0.047，SE = 0.011，p <.001）。然而，基线n-3 PUFA水平在6年内与抑郁症状的后续变化，抑郁症的发作或缓解并不一致。此外，抑郁症和非抑郁症参与者在基线时检测到的n-3 PUFA水平差异在6年内趋于消散（按时间估算的抑郁症：p = 0.011）。最后，与从未抑郁的受试者相比，在基线和6年随访中均处于抑郁状态的受试者在整个随访期间的n-3 PUFA水平始终较低。随着时间的推移，跨波抑郁症的变化并没有始终伴随着n-3 PUFA水平的变化。局限性没有关于中间时间点和EPA含量的数据。结论尽管n-3 PUFA血浆水平与抑郁症和严重程度之间存在显着的横断面联系，但这项为期6年的纵向研究无法确定随时间推移的单向或双向联系。抑郁与n-3 PUFA血浆水平之间的关联不太可能是因果关系。