Ultra-processed food intake and risk of renal cell carcinoma in the NIH-AARP Diet and health study: a prospective cohort analysis

Background Ultra-processed foods (UPF) are widely consumed and have been linked to obesity and hypertension, risk factors of renal cell carcinoma (RCC) and the common clear cell (cc) RCC subtype. We evaluated the association between UPF and RCC. Methods In the NIH-AARP Diet and Health Study, a US prospective cohort, participants with no cancer history at baseline (October 1995–May 1996) were followed until the date of first cancer diagnosis, death, or end of follow-up (December 31, 2018). Diet was self-reported using a food frequency questionnaire (FFQ). FFQ items were assigned to Nova classifications to determine UPF intake (grams per day per 1000 kcal). Probabilistic linkages to cancer registries identified incident RCC diagnoses. Multivariable Cox proportional hazards models estimated hazard ratios (HR) and 95% confidence intervals (CI) for RCC and cc-RCC risk by UPF quartiles. Findings Among 480,347 participants, the median (interquartile range [IQR]) age was 62.6 (57.7–66.6), 59.6% (n = 286,150) were male, 91.3% (n = 438,355) were White. The median (IQR) UPF intake was 293 (197.7–467.2) grams per day per 1000 kcal. There were 3330 RCC diagnoses over follow-up, of which 1216 were cc-RCC. Higher UPF intake was associated with higher RCC [HR (95% CI) Q4 vs Q1 = 1.16 (1.05–1.29), p-trend = 0.0006] and cc-RCC risk [1.38 (1.17–1.62), p-trend <0.0001]. Associations remained but were attenuated when adjusting for body mass index (BMI), diet quality, or hypertension status. Interpretation UPF intake was associated with higher RCC and cc-RCC risk. Further research is needed to elucidate potential mechanisms linking UPF to RCC. Funding Intramural Research Program of the National Institutes of Health.