Food processing/contact materials and cancer risk – NutriNet-Santé prospective cohort

Background

Food processing/contact materials contaminate food with substances such as polycyclic aromatic hydrocarbons (PAHs), brominated flame retardants (BFRs) and per- and polyfluoroalkyl substances (PFAS), but their long-term role in cancer development remains unclear. This study investigated the associations between dietary exposures to these contaminants, alone and in mixtures, and cancer incidence in the French NutriNet-Santé cohort.

Methods

We assessed cumulative time-dependent exposures to 51 food contaminants using repeated 24h-dietary records from 103,212 participants (78.6% women, mean age=42.1 y, SD = 14.5) of the NutriNet-Santé cohort (2009-2024), and quantitative analyses in food matrices from the French total diet study 2 (2006-2009). Associations between contaminant exposures (sex-specific tertiles) and cancer incidence were characterized using multivariable Cox proportional hazards models adjusted for known risk factors. Mixtures effects were explored using sparse PLS-Cox models.

Results

Over a median follow-up time of 7.9 y, 4,438 incident cases of cancer were ascertained. Higher exposure to dietary BFRs was associated with increased incidence of overall (HRT3 vs. T1=1.11, 95% CI[1.02-1.20], ptrend=0.02), colorectal (1.47[1.12-1.93],ptrend=0.002) and obesity-related cancers (1.23[1.10-1.37],poverall<0.001). Total PFAS (1.25[1.00-1.58],poverall=0.048) and total PAHs (1.21[1.02-1.43],ptrend=0.03) were associated with higher breast cancer incidence. 20 contaminants were associated with at least one cancer location. Sparse PLS-Cox models identified contaminants mixtures most associated with each specific cancer.

Conclusions

This large prospective cohort study suggests a potential role for food contaminants such as PFAS, PAHs and BFRs, in cancer development, which is supported by previous in vivo/in vitro experiments showing their interference in key carcinogenesis mechanisms. These elements advocate for stronger regulations, pending further confirmation.

Key messages

• This large prospective cohort study suggests a potential role for food contaminants such as PFAS, PAHs and BFRs, in cancer development.

• These elements advocate for stronger regulations, pending further confirmation.