CRP and migraine disorder: After fully adjusting for potential confounders, including sex, age, race, marital status, poverty, education level, hyperlipidemia, alcohol intake, smoking status, BMI, Hcy, CRP, folate acid supplementation, and serum vitamin B12 levels, the OR (95% CI) for the risk of severe headache or migraine in the Q3 group of serum folate was 0.5 (0.28–0.89) (P = .018).