Background
Experimental evidence suggests that certain polyphenols may be beneficial against the development of colorectal cancer. It is not known, however, if phytoestrogen isoflavones are associated with colorectal cancer development in the Japanese population with higher circulating levels than those found in European populations. We will, therefore, undertake a case-control analysis nested within the JPHC to investigate the relationship
Aims
The study aimed to look into the associations of plasma polyphenol levels with colon cancer risk in the Japan Public Health Center-based prospective study (JPHC Study). Secondly, they aimed to evaluate the reproducibility of 35 plasma polyphenols over a 1-year time period; and also, to examine correlations of 35 polyphenols with food group intakes calculated from weighed food records (WFR) and food frequency questionnaire (FFQ).
How it was done
The researchers conducted a nested-case control study within the JPHC Study. They used prediagnostic plasma samples collected at the time of a five-year follow-up survey to measure the concentration of 35 polyphenols from 375 incident colon cancer cases and 710 matched controls and then analysed the data.
Findings
This was the first prospective study to look at plasma polyphenols and colon cancer risk in the Asian population. It may lead to follow-up projects investigating the association in more recent cohorts, such as JPHC-NEXT Study participants, and the association between plasma polyphenols in colorectal cancer survivors.
Impact
This was the first prospective study to look at plasma polyphenols and colon cancer risk in the Asian population. It may lead to follow-up projects investigating the association in more recent cohorts, such as JPHC-NEXT Study participants, and the association between plasma polyphenols in colorectal cancer survivors.
Grant publication
> Prediagnostic plasma polyphenol concentrations and colon cancer risk: The JPHC nested case–control study Clinical Nutrition, 7 July 2022