Ultra-processed food consumption and the risk of incident chronic kidney disease: a systematic review and meta-analysis of cohort studies

Figures & data

Figure 1. PRISMA flow diagram of the study selection process.

Table 1. Characteristics of the included studies.

Study (year, location)	Study design /follow up (years)/health status	Population	Ultra-processed food assessment method	Outcome definition	Findings	Adjusted variables
		Age
		Male sex (n, %)
ARIC cohort (2022, United States) [21]	Prospective cohort/24 years/healthy subjects	N = 14,679	FFQ/NOVA food classification system/ servings per day	Incident CKD defined as eGFR < 60 mL/min/1.73 m^2 accompanied by ≥ 25% eGFR decline, CKD-related hospitalization or death, or kidney failure with kidney replacement therapy	Participants in the highest tertile of UPF consumption had 24% higher odds of CKD (HR = 1.24; 95% CI: 1.15–1.35).	Age, sex, race-center, total energy intake, education level, smoking status, and physical activity score
		Age = 45–64 years
		(6,593, 44.9%)
Lifelines cohort (2022, Netherlands) [22]	Prospective cohort/3.6 ± 0.9 years/healthy subjects	N = 78,346	FFQ/NOVA food classification system/ proportion of weight	Composite kidney outcome including a ≥ 30% eGFR decline relative to baseline or incident CKD, defined as a de novo occurrence of an eGFR < 60 mL/min/1.73 m^2 at the second study visit compared with the baseline visit	Participants in the highest quartile of UPF consumption were associated with a higher risk of the composite kidney outcome, compared with those in the lowest quartile (OR = 1.27; 95% CI: 1.09–1.47).	Age, sex, baseline eGFR, diabetes, hypertension, cardiovascular disease, physical activity, smoking, total energy intake, education level, Mediterranean diet score, energy-adjusted protein intake, energy-adjusted carbohydrate intake, and energy-adjusted fat intake
		Age = 18–90 years
		(32,595, 41.6%)
TCLSIH cohort (2022, China) [23]	Prospective cohort/2–6 years/healthy subjects	N = 23,775	FFQ/NOVA food classification system/g per 1000 kilocalories per day	CKD defined as eGFR < 60 mL/min/1.73 m^2, albumin-to-creatinine ratio ≥ 30 mg/g, or as having a clinical diagnosis of CKD	Participants in the highest tertile of UPF consumption had 58% higher odds of CKD (HR = 1.58; 95% CI: 1.07–2.34).	Age, sex, education levels, employment status, household income, BMI, smoking status, alcohol drinking status, physical activity, dietary pattern, total energy intake, family history of disease, other kidney disease, high-sensitivity C-reactive protein, albumin and baseline eGFR
		Age ≥ 18 years
		(12,815, 53.9%)
UK Biobank cohort (2022, United Kingdom) [23]	Prospective cohort/10.1 years/healthy subjects	N = 102,332	24-h dietary assessment/NOVA food classification system/g per 1000 kilocalories per day	CKD defined as eGFR < 60 mL/min/1.73 m^2 or as having a clinical diagnosis of CKD, which was ascertained based on medical and death records	Participants in the highest tertile of UPF consumption had 25% higher odds of CKD (HR = 1.25; 95% CI: 1.09-1.43).	Age, sex, education levels, Townsend deprivation index, BMI, smoking status, drinking status, physical activity, healthy dietary score, total energy intake, family history of disease, other kidney disease, high-sensitivity C-reactive protein, and baseline eGFR
		Age = 40–69 years
		(45,231, 44.2%)

Notes: ARIC: atherosclerosis risk in communities; BMI: body mass index; CKD: chronic kidney disease; eGFR: estimated glomerular filtration rate; FFQ: food frequency questionnaire; HR: hazard ratio; OR: odds ratio; TCLSIH: Tianjin chronic low-grade systemic inflammation and health; UPF: ultra-processed food

Table 2. Quality assessment of the included studies.

Study (year, location)	Selection	Comparability	Outcome	NOS score
ARIC Cohort (2022, United States) [21]	3	2	3	8
Lifelines Cohort (2022, Netherlands) [22]	3	2	2	7
TCLSIH Cohort (2022, China) [23]	3	2	2	7
UK Biobank Cohort (2022, United Kingdom) [23]	3	2	3	8

Notes: ARIC: atherosclerosis risk in communities; NOS: Newcastle–Ottawa scale; TCLSIH: Tianjin chronic low-grade systemic inflammation and health

Figure 2. Forest plots demonstrating RR and 95% CI for the pooled results from the random-effects models to evaluate the relationship between UPF consumption and risk of incident CKD.

Table 3. Secondary findings from the included studies.

Study (year, location)	Secondary findings	Adjusted variables
ARIC cohort (2022, United States) [21]	Each additional serving of UPF consumed per day was associated with a 5% higher risk of incident CKD (HR = 1.05; 95% CI: 1.04–1.07).	Age, sex, race-center, total energy intake, education level, smoking status, and physical activity score
	Replacing 1 serving per day of UPF with minimally processed food was associated with a 6% lower risk of incident CKD (HR = 0.94; 95% CI: 0.93–0.96).
Lifelines cohort (2022, Netherlands) [22]	Every 10% increase in the amount of UPF consumed was associated with an 11% higher risk of the outcome (OR = 1.11; 95% CI: 1.06–1.17).	Age, sex, baseline eGFR, diabetes, hypertension, cardiovascular disease, physical activity, smoking, total energy intake, education level, Mediterranean diet score, energy-adjusted protein intake, energy-adjusted carbohydrate intake, and energy-adjusted fat intake
	Participants in the highest quartile had a more rapid annual eGFR decline (β = −0.17; 95% CI: −0.23 to −0.11), compared with those in the lowest quartile.

Notes: ARIC: atherosclerosis risk in communities; CKD: chronic kidney disease; eGFR: estimated glomerular filtration rate; HR: hazard ratio; OR: odds ratio; UPF: ultra-processed food

Figure 3. Forest plots showing sensitivity analysis results.

Figure 4. Funnel plot for evaluating publication bias.

Du S, Kim H, Crews DC, et al. Association between ultraprocessed food consumption and risk of incident CKD: a prospective cohort study. Am J Kidney Dis. 2022;80(5):589–598.e1. doi: 10.1053/j.ajkd.2022.03.016.

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Cai Q, Duan MJ, Dekker LH, et al. Ultraprocessed food consumption and kidney function decline in a population-based cohort in The Netherlands. Am J Clin Nutr. 2022;116(1):263–273. doi: 10.1093/ajcn/nqac073.

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Gu Y, Li H, Ma H, et al. Consumption of ultraprocessed food and development of chronic kidney disease: the Tianjin chronic Low-Grade systemic inflammation and health and UK biobank cohort studies. Am J Clin Nutr. 2023;117(2):373–382. doi: 10.1016/j.ajcnut.2022.11.005.

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Data availability statement

The data that support the findings of this study are available from the corresponding author, [Y.W.], upon reasonable request.