Developing a scoring method for evaluating dietary methodology in reviews of epidemiologic studies

Area of Science:

• Epidemiology
• Nutritional Science
• Oncology

Background:

• Prostate cancer research often examines dietary fat intake.
• Heterogeneity in relative risk (RR) estimates for prostate cancer and dietary fat suggests methodological variations.
• Dietary assessment quality is a potential source of this heterogeneity.

Purpose of the Study:

• To evaluate the quality of dietary assessment methods used in studies investigating prostate cancer and dietary fat.
• To identify factors contributing to the inconsistency in relative risk (RR) estimates.

Main Methods:

• A systematic review of 39 studies published in English was conducted.
• Studies reporting RRs for prostate cancer and dietary fat using food frequency questionnaires (FFQs) were assessed.
• A scoring system evaluated FFQ quality based on item count, validation, interviewer completion, quantitative assessment, and reporting of specific details.

Main Results:

• Of 37 studies using FFQs, only 16 (43%) were classified as high quality.
• Inconsistent reporting of dietary assessment details and limited food items in FFQs were common issues.
• Significant variations exist in the quality of dietary fat assessment in prostate cancer research.

Conclusions:

• The inconsistency in food frequency questionnaire (FFQ) methodology may explain the wide range of relative risk (RR) estimates in prostate cancer and dietary fat studies.
• Improved reporting standards and expert review are crucial for enhancing the quality of dietary assessment in epidemiological research.
• Enhancing the rigor of dietary assessment is imperative for accurate prostate cancer risk prediction.