One group received antioxidants once per day, one group received folinic acid (a folate), one received both antioxidants and folinic acid, and one control group took a placebo.

• 一组每天接受补充抗氧化剂，一组每天接受叶酸，一组每天接受抗氧化剂和叶酸，最后一组是接受安慰剂的对照组。