A Proinflammatory Diet Is Associated with Systemic Inflammation and Reduced Kidney Function in Elderly Adults1, 2, 3

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Abstract

Background: Diet can affect kidney health through its effects on inflammation.

Objective: We tested whether the Adapted Dietary Inflammatory Index (ADII) is associated with kidney function and whether effects of diet on chronic low-grade inflammation explain this association.

Methods: This was an observational analysis in 1942 elderly community-dwelling participants aged 70–71 y from 2 independent cohorts: the Uppsala Longitudinal Study of Adult Men (n = 1097 men) and the Prospective Investigation of Vasculature in Uppsala Seniors (n = 845 men and women). The ADII was calculated from 7-d food records, combining putatively proinflammatory and anti-inflammatory effects of nutrients, vitamins, and trace elements. The ADII was validated against serum C-reactive protein (CRP) concentrations. The estimated glomerular filtration rate (eGFR) was assessed from serum cystatin C (cys) and creatinine (crea). Associations between the ADII and eGFR were investigated, and CRP was considered to be a mediator.

Results: In adjusted analysis, a 1-SD higher ADII was associated with higher CRP (β: 6%; 95% CI: 1%, 10%; P = 0.01) and lower eGFR [Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI)cys: −2.1%; 95% CI: −3.2%, −1.1%; CKD-EPIcys+crea: −1.8%; 95% CI: −2.7%, −0.9%; both P < 0.001]. CRP was also inversely associated with eGFR. Mediation analyses showed that of the total effect of the ADII on kidney function, 15% and 17% (for CKD-EPIcys+crea and CKD-EPIcys equations, respectively) were explained/mediated by serum CRP. Findings were similar when each cohort was analyzed separately.

Conclusions: A proinflammatory diet was associated with systemic inflammation as well as with reduced kidney function in a combined analysis of 2 community-based cohorts of elderly individuals. Our results also suggest systemic inflammation to be one potential pathway through which this dietary pattern is linked to kidney function.

Keywords

diet
ADII
inflammation
CRP
kidney function
eGFR

Abbreviations

ADII
Adapted Dietary Inflammatory Index
CKD
chronic kidney disease
crea
creatinine
CRP
C-reactive protein
cys
cystatin C
eGFR
estimated glomerular filtration rate
EPI
Epidemiology Collaboration
PIVUS
Prospective Investigation of Vasculature in Uppsala Seniors
ULSAM
Uppsala Longitudinal Study of Adult Men

Cited by (0)

1

HX is partially supported by the Karolinska Institutet faculty for funding of postgraduate students (KID). Support was also provided by the Swedish Research Council and Stockholm County Council. Baxter Novum is the result of a grant from Baxter Healthcare Corporation to the Karolinska Institutet.

2

Author disclosures: H Xu, P Sjö gren, J Ä rnlö v, T Banerjee, T Cederholm, U Ris ´ erus, L Lind, and JJ Carrero, no conflicts of interest. B Lindholm is affiliated with Baxter Healthcare Corporation.

3

Supplemental Tables 1–6 are available from the “Online Supporting Material” link in the online posting of the article and from the same link in the online table of contents at http://jn.nutrition.org.