Dietary Exposure Assessment

A food frequency questionnaire (FFQ) with 22-food groups was used to collect exposure information of diet and dietary supplements, with a face-to-face approach. The 22 food groups in this FFQ included wheat and its products (noodles, bread, steamed buns, biscuits, etc.), rice and its products (rice noodles, rice flour, rice cakes, etc.), coarse grain (corn, millet, purple rice, sorghum, oats, buckwheat, etc.), beans and soy products (soybeans, miscellaneous beans, tofu, dried beancurd sticks, soy milk, etc.), red meat (beef, lamb, pork, etc.), poultry meat (chicken, duck, goose, pigeon, etc.), fish and aquatic products (fish, shrimp, crab, shellfish, squid, etc.), eggs (eggs of duck, goose, quail, etc), animal innards (pig liver/belly/intestines, chicken gizzards, foie gras, etc.), fried food (barbecue, fried dough sticks, fried cakes, French fries, etc.), salted food (sauce/preserved mustard, fermented bean curd, salted fish/meat, salted products, etc.), fresh vegetables (potatoes, Chinese cabbage, cabbage, rape, lettuce, pepper, broccoli, cauliflower, loofah, white radish, mustard, eggplant, tomato, carrots, etc.), nuts (melon seeds, chestnuts, peanuts, walnuts, cashews, pistachios, etc.), non-fermented milk (liquid milk, milk powder, etc.), fermented milk (yogurt, cheese, etc.), fresh fruits (apple, banana, pear, peach, orange, tangerine, grape, litchi, longan, watermelon, melon, kiwi, etc.), carbonated beverages (Cola, Sprite, Fanta, etc.), non-carbonated beverages (fruit and vegetable drinks, tea drinks, lactic acid drinks, orange, green tea, black tea, yogurt, etc.), vitamin supplements (vitamin C, B, K, D and multivitamin, etc.), mineral supplements (calcium, iron, zinc, etc.), healthcare products (traditional Chinese medicine, health products, etc.), and fish oil (fish oil, cod liver oil, etc.). The specific foods contained in each food group were shown in the Supplementary Table S1. A series of food pictures were provided to each subject to help recall food intake information when the survey was conducted. Subjects were asked to answer whether consumed a certain food group over the past twelve months. If their response was yes, their intake frequency of this certain food group further needed to be provided. Five defined options of the intake frequency were provided in advance (“<1 time per month”, “1 to 3 times per month”, “1 to 3 times per week”, “4 to 6 times per week”, “≥1 time per day”).