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 longchain 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 nonsignificantly higher eGFR_cre and significantly higher eGFR_cys (P = 0.016). In addition, eGFR_cys in T2+T3 of (EPA+DHA):AA was significantly higher than that in T1 (adjusted mean eGFR_cys, T1: 87 ml/min/1.73m2, T2+T3: 91 ml/min/1.73m2; 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.