Associations between plasma levels of omega-3 fatty acids and subsequent allergic diseases.

Background: Some metabolites of omega-3 fatty acids, such as Maresin have been reported as inflammation converging substances and are suspected to be related to various inflammatory diseases. However, limited number of clinical researches on the association between omega-3 fatty acid as blood levels and inflammatory diseases were published.

Methods: We conducted a retrospective cohort study at St. Luke's International Hospital from January 2007 to December 2017. We included all adult patients who had measured plasma fatty acids levels as a part of clinical practice. We excluded patients who had a prior medical history of any allergic diseases. Our primary outcomes were the development of any allergic diseases. The outcomes were compared with Cox proportional hazard model between patients quartered by baseline plasma levels of n-3 PUFAs, such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) adjusting for potential confounders.

Results: A total of 1506 patients were included. The mean age was 63.3 (SD: 12.5) years and 1066 (70.8%) were male. The mean EPA levels were 84.09 (SD: 58.67) μg/ml and DHA levels were 139.61 (SD: 60.47) μg/ml. Neither EPA nor DHA levels were significantly associated with the development of allergic disease (log-rank test; p = 0.933, p = 0.908, respectively) in bivariable analyses, or multivariable analyses (hazard ratios [HRs]: 0.90-0.97 for EPA; and HRs: 0.89-0.90 for DHA).

Conclusions: The EPA and DHA levels were related to C-reactive protein (CRP) of inflammation maker, but non-significant associated with development allergic diseases.