Validity and reproducibility of the food-frequency questionnaire used in the Shanghai Men's Health Study

We evaluated the validity and reproducibility of the FFQ used in the Shanghai Men's Health Study (SMHS). The study included 195 randomly selected participants of the SMHS who completed one FFQ at baseline, twelve 24-hour dietary recalls (24-HDR) (once a month for twelve consecutive months) and a second FFQ at the end of the study. The FFQ accounted for 88·78 % of the foods recorded in the 24-HDR surveys. The validity of the FFQ was evaluated by...