W31 - 4DFR on DM Ovarian Cancers
This page provides study documentation for Core Study W31. For description of the specimen results, see Specimen Results Description (open to public). Data sets of the specimen results are included in the existing WHI datasets located on the WHI Data on this site (sign in and a completed Data Distribution Agreement are required; see details on the Data site).
Investigator Names and Contact Information
Core Study approved the the WHI Steering Committee
Introduction/Intent
The DM and other cancer priority paper for WHI has examined the effect of the low-fat dietary intervention on ovarian and other cancers. The analyses, based upon FFQ are provocative for a potential relationship with ovarian cancer . These results have the potential to add considerably to findings of interest from the DM trial. However, the interpretation of the ovarian cancer data comparison could be enhanced by the inclusion of case-only analyses using the 4DFRs, in the same manner that was done for the DM main papers (for breast cancer , colorectal cancer, CHD), to examine the hazard ratio in relation to baseline diet, particularly in relation to baseline % energy from fat...
FFQ % energy from fat is substantially distorted by the use of the FFQ as a screening tool in the DM trial, and may be weak evaluation tool. Within the DM priority paper, the hazard ratio for DM effect on breast cancer did not relate to FFQ % energy from fat, whereas it did (p=0.04) to 4DFR % energy from fat. It is unknown whether this same type of interaction will arise for the ovarian cancer HR.
We propose to analyze the four day food records for the 160 invasive ovarian cancer cases for a case-only analysis using the techniques applied to the 4DFR for breast cancer, colorectal cancer, and CVD cases in the priority papers. By completing analysis of the 4DFR for the ovarian cancer cases, these data would allow closer examination of the relationship between change in fat intake and cancer risk and will allow for additional analyses as to the benefit of using 4DFR vs FFQ for analysis. Although the DM and other cancer ms has been submitted to JNCI, regardless of the findings of the 4DFR analyses, it is the authors plan to replace the FFQ % energy from fat display in Table 3 in the manuscript by a 4DFR display at the time of revision.
Operationally, WHI made the investment several months ago to assemble the baseline 4DFRs from each of the CCs/FCs, so that writing groups would be in a position to use them for analyses that may advance knowledge in diet and chronic disease. The ovarian cancer 4DFR analyses will be available for other ovarian cancer analyses in WHI (perhaps along the lines of how the 4DFRs have already been used for breast cancer, leading to a positive association between % energy from fat and breast cancer in the DM control group when a 4DFR was used to assess diet, in contrast to a lack of association if a FFQ was used--Freedman et al Int J Epid 2006).
Results/Findings