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(OR25-01-26) Dietary Carbon Footprint and the Risk of Colorectal Cancer in the NIH-AARP Diet and Health Study

Tuesday, July 28, 2026
8:30 AM - 8:42 AM ET
Location: Maryland Ballroom D

    Presenting Author(s)

  • AW

    Amelia Willits-Smith, PhD

    Postdoctoral Cancer Research Training Award (CRTA) Fellow
    National Cancer Institute, National Institutes of Health
    Rockville, Maryland, United States

    Disclosure information not submitted.

    • Co-Author(s)

  • Jill Reedy, PhD, MPH, RDN (she/her/hers)

    Branch Chief
    National Cancer Institute, National Institutes of Health
    Bethesda, Maryland, United States

  • DR

    Donald Rose

    Tulane University
    New Orleans, Louisiana, United States

  • LK

    Lisa Kahle

    Information Management Systems (IMS)
    Calverton, Maryland, United States

  • KH

    Kirsten A. Herrick, MSc, PhD (she/her/hers)

    Program Director
    National Cancer Institute, National Institutes of Health
    Rockville, Maryland, United States

Disclosure(s):
Jill Reedy, PhD, MPH, RDN: No relevant financial relationship(s) with ineligible companies to disclose.
Kirsten A. Herrick, MSc, PhD: No relevant financial relationship(s) with ineligible companies to disclose.
Objectives: There is growing interest in the potential health and sustainability co-benefits of dietary patterns, but few dietary assessments include measures of foods’ environmental impact and little is known about these interrelationships for colorectal cancer (CRC). This study examines the relationship of diet carbon footprint (CF) – a measure of the emissions released in producing food for a diet – with diet quality and CRC risk in a large US cohort of older adults.

Methods: We linked data from the NIH-AARP Diet & Health Study’s 124-item food frequency questionnaire (FFQ) to DataFRIENDS to estimate diet CF (kg CO2-equivalents per 2000 kcal). Participants with no cancer history who had FFQ and sociodemographic data (n=276,940 males & 188,496 females) were followed from baseline (1995-1996, at ages >=50 years) through 2018. CRC cases were identified through probabilistic linkage to state cancer registries. Sex-stratified multivariable Cox proportional hazards models were used to estimate CRC risk for higher- compared to lower-CF diets, adjusting for energy, age, race or ethnicity, education, body mass index, physical activity, and smoking. Healthy Eating Index-2020 (HEI) component and total scores were computed to assess the relationship between diet CF and diet quality.

Results: In fully adjusted models, the risk of CRC was higher among consumers of higher-CF compared to lower-CF diets. Compared to those in CF quintile 5, CRC risks were 9% lower in quintile 3 (male HR: 0.91 [0.85, 0.97]; female HR: 0.91 [0.83, 0.99]) and 8-12% lower in quintile 2 (male HR: 0.92 [0.86, 0.98]; female HR: 0.88 [0.80, 0.96]). Higher diet CF was also associated with lower total HEI (inversely correlated for males: r=-.219, p< 0.001; females: r=-.107, p< 0.001). Seven HEI component scores differed between higher-CF and lower-CF diets. The largest differences were in Saturated Fat and Fatty Acid Ratio scores, with less optimal scores in CF quintile 5, reflecting higher intake of saturated fat.

Conclusions: Older Americans who reported a higher diet CF also had poorer diet quality and an increased risk of CRC. Foods higher in saturated fats often have higher carbon footprints, which might be driving these results, suggesting potential health and sustainability co-benefits of reducing them.

Funding Sources: None