CHAPTER 14: Selenium Status Assessment by Questionnaire in Clinical and Cardiovascular Studies

The emerging role of selenium in cardiovascular disease and other clinical conditions has attracted the research enthusiasm of clinicians and scientists. To study the clinical effects of selenium on cardiovascular and other chronic diseases, the long-term exposure level of selenium should be adequately assessed. In this chapter, we describe and appraise the questionnaire-based assessment techniques of selenium status, focusing on the use of the food frequency questionnaire (FFQ) in the clinical studies of cardiovascular and chronic diseases. We shall also dissect its pros and cons at the methodology and execution levels in comparison with direct measurement of clinical biomarkers of selenium. As is shown, both questionnaire-based assessment and clinical biomarkers of selenium have their own merits and limitations. Combined assessment approaches can allow interrogation of both short-term and long-term exposure estimates and also allow crossvalidation. The novel findings of genetic polymorphisms related to mechanistic pathways of selenium provide exciting future research opportunities for any diet–gene interactions, when studied in conjunction with the questionnaire-based assessments.