Ultra-processed products and risk of liver cancer: A prospective cohort study

Several studies have shown positive associations between ultra-processed foods and drinks and cancer risk. However, evidence remains limited for liver cancer. We aimed to evaluate the associations between ultra-processed foods and drinks and liver cancer risk.

We included 73,119 participants (22,431 Whites, 47,837 Blacks, 2851 other race) from the Southern Community Cohort Study. Ultra-processed products were defined based on the Nova classification using data from a validated food frequency questionnaire and calculated as percentage of daily foods by weight. Incident liver cancer and vital status were ascertained via linkages to state cancer registries and the National Death Index as of December 31, 2019.

With a median of 13.9 year's follow-up, we documented 453 incident liver cancer cases. Participants with higher intake of ultra-processed foods had an elevated risk of liver cancer (hazard ratios [HR] _{Tertile 3 vs. tertile 1} 1.69, 95% confidence intervals [CI]: 1.28-2.22; P_trend<0.001). The subclasses of ultra-processed foods, such as ultra-processed grains and fried potatoes (HR _{T3 vs. T1} 1.29, 95% CI: 1.01-1.65; P_trend = 0.03), processed protein foods (HR _{T3 vs. T1} 1.49, 95% CI: 1.14-1.94; P_trend = 0.007) and mixed dishes (HR _{T3 vs. T1} 1.39, 95% CI: 1.09-1.77; P_trend = 0.01), were positively associated with liver cancer risk. No significant association was found for ultra-processed drinks (HR _{T3 vs. T1} 0.85, 95% CI: 0.67-1.07; P_trend = 0.16).

In a prospective cohort with predominantly low-income Southern US adults, we found certain ultra-processed foods were associated with a higher risk of liver cancer. Further studies are needed to confirm our findings.