Effects of dietary fatty acid on all-cause mortality according to the kidney function based on the nationwide population study

Background: Although the relationship between fatty acids (FAs) and the risk of all-cause mortality has been long discussed, there is little evidence about the impact of each FA component on all-cause mortality by kidney function status.

Methods: We used data from the U.S. National Health and Nutrition Examination Survey 1999-2016. The intake of FAs was estimated as a percentage of total energy using a 1-day 24-hour dietary recall and divided by quartiles; the first quartile was regarded as a reference. We used a multivariate Cox proportional hazard model to identify the impact of FAs on all-cause mortality.

Results: Among 44,332 participants, during 129.0 ± 62.4 months of follow-up, there were 1,623 (6.2%), 3,109 (22.3%), and 2,202 deaths (53.1%) in the estimated glomerular filtration rate (eGFR) ≥90, 60-90, and <60 mL/min/1.73 m2 groups, respectively. Higher intake of SFAs significantly increased the risk of all-cause mortality in participants with eGFR 60-90 mL/min/1.73 m2 (adjusted hazard ratio, 1.20 in the 4th quartile). Likewise, higher intake of most PUFAs (octadecadienoic acid, octadecatrienoic acid, omega-6, and omega-3) significantly decreased the risk of all-cause mortality in participants with eGFR 60-90 mL/min/1.73 m2 . These effects of both SFAs and PUFAs were attenuated in participants with eGFR ≥90 and <60 mL/min/1.73 m2 .

Conclusion: The impact of dietary FAs on all-cause mortality was prominent in participants with eGFR 60-90 mL/min/1.73 m2 . More specified and targeted counseling for restricting SFAs and encouraging PUFAs needs to be considered, especially for participants with marginally decreased kidney function.