Ultraprocessed Foods and Kidney Disease Progression, Mortality, and Cardiovascular Disease Risk in the CRIC Study

Abstract

Rationale & objective: Ultraprocessed foods are widely consumed in the United States and are associated with cardiovascular disease (CVD), mortality, and kidney function decline in the general population. We investigated associations between ultraprocessed food intake and chronic kidney disease (CKD) progression, all-cause mortality, and incident CVD in adults with chronic kidney disease (CKD).

Study design: Prospective cohort study.

Setting & participants: Chronic Renal Insufficiency Cohort Study participants who completed baseline dietary questionnaires.

Exposure: Ultraprocessed food intake (in servings per day) classified according to the NOVA system.

Outcomes: CKD progression (≥50% decrease in estimated glomerular filtration rate [eGFR] or initiation of kidney replacement therapy), all-cause mortality, and incident CVD (myocardial infarction, congestive heart failure, or stroke).

Analytical approach: Cox proportional hazards models adjusted for demographic, lifestyle, and health covariates.

Results: There were 1,047 CKD progression events observed during a median follow-up of 7 years. Greater ultraprocessed food intake was associated with higher risk of CKD progression (tertile 3 vs tertile 1, HR, 1.22; 95% CI, 1.04-1.42; P=0.01 for trend). The association differed by baseline kidney function, such that greater intake was associated with higher risk among people with CKD stages 1/2 (eGFR≥60mL/min/1.73m²; tertile 3 vs tertile 1, HR, 2.61; 95% CI, 1.32-5.18) but not stages 3a-5 (eGFR<60mL/min/1.73m²; P=0.003 for interaction). There were 1,104 deaths observed during a median follow-up of 14 years. Greater ultraprocessed food intake was associated with higher risk of mortality (tertile 3 vs tertile 1, HR, 1.21; 95% CI, 1.04-1.40; P=0.004 for trend).

Limitations: Self-reported diet.

Conclusions: Greater ultraprocessed food intake may be associated with CKD progression in earlier stages of CKD and is associated with higher risk of all-cause mortality in adults with CKD.

Plain language summary: Ultraprocessed foods are industrial formulations produced using ingredients and processes that are not commonly used in culinary preparations and contain few, if any, intact unprocessed foods. Ultraprocessed foods are widely consumed in the United States, and high intakes of such foods have been linked to cardiovascular disease, kidney disease, and mortality in the general population. In this study, we found that greater intake of ultraprocessed foods was associated with higher risk of kidney disease progression and mortality in adults with chronic kidney disease. Our findings suggest that patients with kidney disease may benefit from greater consumption of fresh, whole, and homemade or hand-prepared foods and fewer highly processed foods.

Keywords: CRIC Study; NOVA; dietary intake; epidemiology; kidney disease; nutrition; ultraprocessed foods.

Figure 1.

Proportion of total ultra-processed foods (servings/day) contributed by each food category in the Chronic Renal Insufficiency Cohort Study. Beverages: fruit drinks, meal replacement beverages, soft drinks; snacks and sweets: crackers, potato chips, corn chips, pretzels, energy bars, frozen yogurt, ice cream, cake, cookies, brownies, doughnuts, sweet rolls, Danish, fruit crisp/cobbler, pies, chocolate candy, other candy; grains: ready-to-eat breakfast cereals, bagels, English muffins, bread, rolls, corn bread, biscuits, sweet muffins, dessert breads; fats and oils: salad dressing, margarine, cream cheese, mayonnaise, non-dairy creamer; protein foods: roast beef, poultry cold cuts, deli-style ham, other cold cuts, hot dogs, bacon, sausage, fish sticks, fried fish, tofu* and soy meat products, egg substitute; mixed dishes: stuffing, dumplings, chili, Mexican foods, pizza; vegetables: French fries, home fries, hash browned potatoes, tater tots; condiments and sauces: cheese sauce, catsup, gravy; alcoholic beverages: liquor, mixed drinks; sugars: jams, jellies, honey*. *While not ultra-processed, intake of these foods were queried in conjunction with other ultra-processed foods and could not be separately quantified.

Figure 1.

Proportion of total ultra-processed foods (servings/day) contributed by each food category in the Chronic Renal Insufficiency Cohort Study. Beverages: fruit drinks, meal replacement beverages, soft drinks; snacks and sweets: crackers, potato chips, corn chips, pretzels, energy bars, frozen yogurt, ice cream, cake, cookies, brownies, doughnuts, sweet rolls, Danish, fruit crisp/cobbler, pies, chocolate candy, other candy; grains: ready-to-eat breakfast cereals, bagels, English muffins, bread, rolls, corn bread, biscuits, sweet muffins, dessert breads; fats and oils: salad dressing, margarine, cream cheese, mayonnaise, non-dairy creamer; protein foods: roast beef, poultry cold cuts, deli-style ham, other cold cuts, hot dogs, bacon, sausage, fish sticks, fried fish, tofu* and soy meat products, egg substitute; mixed dishes: stuffing, dumplings, chili, Mexican foods, pizza; vegetables: French fries, home fries, hash browned potatoes, tater tots; condiments and sauces: cheese sauce, catsup, gravy; alcoholic beverages: liquor, mixed drinks; sugars: jams, jellies, honey*. *While not ultra-processed, intake of these foods were queried in conjunction with other ultra-processed foods and could not be separately quantified.

Figure 2.

Hazard ratio and 95% confidence interval for risk of chronic kidney disease progression associated with ultra-processed food consumption in the Chronic Renal Insufficiency Cohort Study. Solid line represents the hazard ratio, modeled using restricted cubic spline with knots at the 5th, 35th, 65th, and 95th percentiles of ultra-processed food consumption (servings/day). Dashed lines represent 95% confidence intervals for hazard ratios. The reference level was set at the 35th percentile of intake. Hazard ratios adjusted for age, sex, total energy intake, race/ethnicity, education, income, smoking status, physical activity, and study site. The underlying grey histogram presents the distribution of participants’ ultra-processed food consumption (servings/day).

Figure 3.

Association between ultra-processed food consumption and risk of chronic kidney disease progression in subgroups. Hazard ratios for tertile 3 versus tertile 1 adjusted for age, sex, total energy intake, race/ethnicity, education, income, smoking status, physical activity, and study site. P-values for likelihood ratio tests comparing adjusted models with versus without interaction terms for subgroups. Abbreviations: CI, confidence interval; CKD, chronic kidney disease; eGFR, estimated glomerular filtration rate; HR, hazard ratio; LR, likelihood ratio

Figure 4.

Hazard ratio and 95% confidence interval for risk of all-cause mortality associated with ultra-processed food consumption in the Chronic Renal Insufficiency Cohort Study. Solid line represents the hazard ratio, modeled using restricted cubic spline with knots at the 5th, 35th, 65th, and 95th percentiles of ultra-processed food consumption (servings/day). Dashed lines represent 95% confidence intervals for hazard ratios. The reference level was set at the 35th percentile of intake. Hazard ratios adjusted for age, sex, total energy intake, race/ethnicity, education, income, smoking status, physical activity, and study site. The underlying grey histogram presents the distribution of participants’ ultra-processed food consumption (servings/day).