DALYs	Disability-adjusted life years
EIA	Enzyme immunoassay
ELISA	Enzyme-linked immunoassay
Hcy	Homocysteine
HELENA	Nutrition and lifestyle in European adolescents
HHcy	Hyperhomocysteinemia
ICHD	International classification of headache disorders
IHS	International Headache Society
MA	Migraine with aura
HPLC	High-performance liquid chromatography
MeSH	Medical subject heading
MTHFR	Methylenetetrahydrofolate reductase
NMDA	N-methyl-D-aspartate
NOS	Newcastle–Ottawa scale
PICOS	Population Intervention Comparison Outcome and Study design
PRISMA	Preferred Reporting Items for Systematic Reviews and Meta-Analyses
QUIN	Quinolinic acid
SD	Standard deviation
SMD	Standardized mean difference
YLDs	Years lived with disability
YLLs	Years of life lost