The assessment of dietary carotenoid intake of the Cardio-Med FFQ using food records and biomarkers in an Australian cardiology cohort: a pilot validation.

Dietary carotenoids are associated with lower risk of CHD. Assessment of dietary carotenoid intake using questionnaires can be susceptible to measurement error. Consequently, there is a need to validate data collected from FFQs which measure carotenoid intake. This study aimed to assess the performance of the Cardio-Med Survey Tool (CMST)-FFQ-version 2 (v2) as a measure of dietary carotenoid intake over 12-months against plasma carotenoids biomarkers and 7-Day Food Records (7DFR) in an Australian cardiology cohort. Dietary carotenoid intakes (β- and α-carotene, lycopene, β-cryptoxanthin and lutein/zeaxanthin) were assessed using the 105-item CMST-FFQ-v2 and compared to intakes measured by 7DFR and plasma carotenoid concentrations. Correlation coefficients were calculated between each dietary method, and validity coefficients (VCs) were calculated between each dietary method and theoretical true intake using the 'methods of triads'. Thirty-nine participants aged 37-77 years with CHD participated in the cross-sectional study. The correlation between FFQ and plasma carotenoids were largest and significant for β-carotene (0.39, p =0.01), total carotenoids (0.37, p =0.02) and β-cryptoxanthin (0.33, p =0.04), with weakest correlations observed for α-carotene (0.21, p =0.21) and lycopene (0.21, p =0.21). The FFQ VCs were moderate (0.3-0.6) or larger for all measured carotenoids. The strongest were observed for total carotenoids (0.61) and β-carotene (0.59), while the weakest were observed for α-carotene (0.33) and lycopene (0.37). In conclusion, the CMST-FFQ-v2 measured dietary carotenoids intakes with moderate confidence for most carotenoids, however, there was less confidence in ability to measure α-carotene and lycopene intake, thus further research is warranted using a larger sample.