AssociationsofTotalProteinorAnimalProtein IntakeandAnimalProteinSourceswithRiskof KidneyStones:ASystematicReviewand Dose–ResponseMeta-Analysis

Abstract

We conducted the present systematic review and meta-analysis to evaluate the association of total protein, animal protein, and animal protein sources with risk of kidney stones in the general population. A literature search was performed in PubMed/Medline, Scopus, and EMBASE up to July 2021. We assessed the credibility of evidence based on NutriGrade scoring system. A total of 14 prospective cohort studies were included. A positiveassociationwasobservedbetweenhigherintakeofnondairyanimalprotein(RR:1.11;95%CI:1.03,1.20;I2=0%,n=4),totalmeatandmeat products(RR:1.22;95%CI:1.09,1.38;I2=13%,n=3),andprocessedmeat(RR:1.29;95%CI:1.10,1.51;I2=0%,n=2)withriskofkidneystones.There was an inverse associationbetween higher intake of dairy protein and riskof kidney stones (RR: 0.91; 95% CI: 0.84, 0.99; I2 =0%,n =4). Moreover, each 100-gincrement of red meat intake was significantly associated with increased risk of kidney stones (RR: 1.39; 95% CI: 1.13, 1.71). According to the NutriGrade scoring system, the credibility of evidence for most of the exposures was rated as low. We found some kind of publication bias in the association of animal protein intake and risk of kidney stones, according to Egger’s and Begg’s tests. In the sensitivity analysis of processed meataswellasdairyconsumptionwithriskofkidneystonesweobservedineachindividualanalysis,1studychangedtheoverallestimate.Further observational studies are needed to confirm the present results. The protocol of the present study was registered in the International Prospective RegisterofSystematicReviews(PROSPERO)database(CRD42021230125:https://www.crd.york.ac.uk/PROSPERO).