Background: Prostate cancer remains the second most common cause of cancer-related death in men in the United States (Siegel et al. 2017). Observational studies of patients with prostate cancer have found associations between diet and prostate cancer severity, but the evidence is inconsistent or inconclusive. The purpose of this thesis is to implement a validated international healthy diet score and evaluate whether or not it is associated with prostate cancer severity.
Objective: The objectives of this thesis were:
Chapter 1: examine whether an association exists between diet quality, using the validated Healthy Diet Score, and the severity of prostate cancer, and
Chapter 2: examine the agreement between two methods of dietary data collection (an abridged FFQ and a longer previously validated FFQ) with respect to macronutrients and main food groups.
Methods: We used observational data from the Randomized Intervention for Cardiovascular and Lifestyle Risk Factors in Prostate Cancer Patients (RADICAL PC), a multi-centre Canadian prospective cohort study into which men with a new diagnosis of prostate cancer or who were being treated with androgen deprivation therapy were enrolled. To complete objective 1 (Chapter 1) of this dissertation, a cross-sectional analysis was completed using baseline data collected in the RADICAL PC study. In order to evaluate the association of diet with prostate cancer severity, the relationship between the Healthy Diet Score and prostate cancer severity (stage and grade) was assessed. The second objective (Chapter 2) is a comparability sub-study comparing an abridged FFQ with a long, validated FFQ in a subgroup of participant (N=130) enrolled in the RADICAL PC study.
Results:
Chapter 1: In the cross-sectional analysis of baseline data collected in RADICAL PC, a higher diet score was not significantly associated with prostate cancer severity. An association between age and the high-risk prostate cancer category was found to be statistically significant (OR: 1.04, 95%CI 1.02-1.05, p<0.00).
Chapter 2: There was good agreement between the abridged FFQ and long FFQ for carbohydrates, proteins, whole wheat, refined grains, fish, dairy, potatoes, fruits, nuts, and soft drinks (Spearman rank correlation >0.5). Food groups including fried foods, processed meats, vegetables and total fats (nutrients) were found to have moderate correlation (Spearman rank correlation between 0.3-0.5). There was low correlation for legumes, sugars and oils. Bland-Altman plots showed good absolute agreements between the two methods, and reliability test using Spearman’s correlation showed moderate to good correlation (0.45 to 0.75 among most food groups.
Conclusion:
There was no clear association between a healthier diet and prostate cancer severity in men with newly diagnosed prostate cancer. There was adequate agreement between the abridged SFFQ and the long FFQ of the expected food groups, and thus the SFFQ can be considered an appropriate tool to use for measuring diet among prostate cancer patients for some food groups and nutrients. / Thesis / Master of Health Sciences (MSc)
| Identifer | oai:union.ndltd.org:mcmaster.ca/oai:macsphere.mcmaster.ca:11375/25298 |
| Date | January 2020 |
| Creators | Savija, Nevena |
| Contributors | Leong, Darryl, Health Research Methodology |
| Source Sets | McMaster University |
| Language | English |
| Detected Language | English |
| Type | Book |
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