TABLE 1.
Eligibility criteria for inclusion in the review
| Category | Inclusion criteria | Exclusion criteria |
|---|---|---|
| Study design | Mendelian randomization (MR) studies Genetic instrumental variable analysis studies Genome-wide Association Study (GWAS or GWA study) Whole Genome Association Study (WGAS or WGA study) |
Any reviews or meta-analyses Case-cohort studies Case reports or case series Cohort studies Conference proceedings or abstracts cross-sectional studies Letters to the editor Randomized or nonrandomized controlled trials Uncontrolled trials |
| Study duration | No restriction | None |
| Sample size | No restriction | None |
| Intervention/exposure | For GWAS studies: Single nucleotide polymorphisms (SNPs) For MR studies: 1. Any instrumental variable with SNPs associated with choline/choline metabolites or 2. Serum or plasma choline or choline-related metabolites. Choline/choline metabolites of interest include:
|
GWAS studies: No SNPs MR studies: No choline/choline metabolites or associated SNPs. |
| Comparator | No restriction | None |
| Outcomes | For GWAS studies: Serum or plasma choline or choline-related metabolites including:
|
GWAS studies: No choline/choline metabolites. MR studies: No health outcomes |
| Date of publication | No restriction | None |
| Publication status | Peer-reviewed publications | Publications that are not peer-reviewed |
| Language of publication | No restriction | None |
| Country | No restriction | None |
| Study participants | Humans | Animals |
| Age of study participants | No restriction | None |
| Health status of participants | No restriction | None |