Association Between Serum Long-Chain n-3 and n-6 Polyunsaturated Fatty Acid Profiles and Glomerular Filtration Rate Assessed by Serum Creatinine and Cystatin C Levels in Japanese Community-Dwellers

BACKGROUND: Plasma concentration of n-3 polyunsaturated fatty acids (PUFAs) has been reported to be associated with renal function in Western populations. However, few studies have investigated the association between serum long-chain n-3 and n-6 PUFA profiles and renal function in a Japanese population with high marine-derived long-chain n-3 PUFA intake. METHODS: A cross-sectional study was performed in 549 Japanese rural community-dwellers aged 40 to 64 years. In adjusted analysis of covariance, we assessed the relationship between estimated glomerular filtration rate (eGFR) and tertiles of serum long-chain n-3 and n-6 PUFA profiles ([eicosapentaenoic acid {EPA} + docosahexaenoic acid {DHA}]:arachidonic acid [AA]). GFR was estimated by Japanese specific equations using serum creatinine and cystatin C (eGFR(cre) and eGFR(cys)). Using multivariate-adjusted linear regression models, we also assessed the relationships between eGFRs and several n-3 and n-6 PUFAs, which have been suggested to be associated with renal function. RESULTS: In all participants, higher dietary fish intake as assessed by a semi-quantitative questionnaire was associated with higher serum value of (EPA+DHA):AA. Participants in the higher (EPA+DHA):AA tertiles had non-significantly higher eGFR(cre) and significantly higher eGFR(cys) (P = 0.016). In addition, eGFR(cys) in T(2)+T(3) of (EPA+DHA):AA was significantly higher than that in T(1) (adjusted mean eGFR(cys), T(1): 87 ml/min/1.73 m(2), T(2)+T(3): 91 ml/min/1.73 m(2); P < 0.01). Among the PUFAs, only (EPA+DHA) was significantly associated with eGFR(cys). CONCLUSIONS: Serum (EPA+DHA):AA, which reflects an individual’s fish intake, might be associated with eGFR(cys) in Japanese community-dwellers.