Colorectal cancer (CRC) is the third most commonly diagnosed cancer in American men and women with ≥130,000 new cases each year. Several dietary patterns have been associated with CRC risk but underlying mechanisms are not fully understood. Researchers thus propose to integrate dietary patterns and metabolomics data to comprehensively investigate biological pathways linking dietary patterns and CRC risk.

Several dietary patterns have been associated with colorectal cancer (CRC) risk but underlying mechanisms are not fully understood. Also, evidence is lacking on the consistency of dietary guidelines for overall health and CRC prevention given that it is not feasible to have an optimal diet for every disease. Furthermore, metabolomic profiling has not been widely assessed with respect to CRC risk. Metabolomics is uniquely suited to assess metabolic responses to dietary stimuli, given that it is situated downstream to all the other "omics". Building on prior work in hypothesis-driven dietary patterns and CRC prevention, the researchers seek to fill these knowledge gaps by proposing to: 1) use a standardized methodology to compare the best diet for overall health with the best diet for CRC prevention, and further determine if any associations of dietary patterns with CRC prevention are mediated by mechanisms involving inflammation and insulin; 2) determine metabolites that may mediate the association of dietary intake with CRC risk. The researchers will utilize two large prospective cohort studies, the Nurses' Health Study (NHS) and the Health Professionals Follow-up Study (HPFS), in which dietary and nondietary data have been collected every 2 to 4 years among 173,230 women and men over the last ≥30 years, with ≥3,400 CRC cases and ≥43,800 all-cause deaths. This integrated interrogation of dietary patterns and metabolomics data will inform the design of guidelines for healthful lifestyles that are optimized for CRC prevention.

Inclusion Criteria:

-Adult health professionals

Exclusion Criteria:

• Any cancer except nonmelanoma skin cancer
• Did not complete a food frequency questionnaire during follow-up
• Had implausible values for total energy intake (<600 or >3500 kcal/d for women and <800 or >4,200 kcal/d for men) at study entry

The Nurses' Health Study (NHS) and the Health Professionals Follow-up Study (HPFS). The NHS recruited 121,701 registered female nurses aged 30 to 55 years at baseline in 1976, and the HPFS enrolled 51,529 male health professionals aged 40 to 75 years at baseline in 1986 in the United States. In both cohorts, questionnaires were sent at baseline and every two years thereafter to collect and update demographic, lifestyle, medical, and other health-related information. Since the inception of both cohorts, participants have completed self-administered questionnaires every 2 years, providing updated information on medical and lifestyle factors. Every 2 to 4 years, participants receive validated semi-quantitative food frequency questionnaires (FFQ) for dietary assessments.