Dietary vitamin E and tocopherol isoform intake and the progression of chronic kidney disease.

Abstract

Background and hypothesis: It is unclear whether dietary vitamin E and tocopherol isoform intake is associated with health outcomes in patients with chronic kidney disease (CKD). We hypothesize that different dietary tocopherol isoforms have different health effects in people with CKD. Therefore, we aimed to investigate the association between dietary vitamin E and tocopherol isoforms and risks of CKD progression and all-cause mortality in patients with CKD.

Methods: In this prospective cohort study, 3 791 participants with CKD in the Chronic Renal Insufficiency Cohort (CRIC) were included. The main exposures included dietary vitamin E and tocopherol isoforms, which were estimated by the validated Diet History Questionnaire at baseline, year 2, and year 4 before the study outcome was diagnosed. The primary outcome was CKD progression, defined as a 50% decline in the estimated glomerular filtration rate from baseline or initiation of kidney replacement therapy. The secondary outcome was all-cause mortality.

Results: During a median follow-up of 5.5 years, 1 188 (31.3%) CKD progression events occurred. There was an L-shaped relationship between total vitamin E intake and risks of CKD progression and all-cause mortality. Regarding dietary tocopherol isoforms, there was an L-shaped relationship of dietary beta-tocopherol with risks of CKD progression and all-cause mortality, a reversed J-shaped relationship between dietary gamma-tocopherol and the risk of CKD progression and a U-shaped association between dietary delta-tocopherol and the risk of CKD progression. There was no significant association between dietary alpha-tocopherol and risks of CKD progression and all-cause mortality.

Conclusions: There was an L-shaped association between total vitamin E and CKD progression in patients with CKD. Different dietary tocopherol isoforms have different relationships with CKD progression in patients with CKD, which included an L-shaped association for beta-tocopherol, a reversed J-shaped association for gamma-tocopherol, a U-shaped association for delta-tocopherol and a non-significant association for alpha-tocopherol.