title: Homocysteine and the risk of age-related macular degeneration: a systematic review and meta-analysis.
abstract: Contrasting results have been reported regarding the associations between plasma total homocysteine (tHcy) and B vitamin levels and age-related macular degeneration (AMD) risk. Thus, we aimed to systematically evaluate these associations. Relevant case control studies in English were identified via a thorough search of the PubMed, Medline, and Embase databases from inception to June 2014. The results were pooled using Review Manager 5.2.1. Eleven studies (including 1072 cases and 1202 controls) were eligible for analysis of tHcy levels; additionally, 3 studies (including 152 cases and 98 controls) were eligible for analysis of folic acid and vitamin B12 levels. The cumulative results demonstrated that the plasma tHcy level among the AMD cases was 2.67 μmol/L (95% confidence interval [CI], 1.60-3.74) higher than that among the controls. In contrast, the vitamin B12 level among the AMD cases was 64.16 pg/mL (95% CI, 19.32-109.00) lower than that among the controls. Subgroup analyses showed that the folic acid level was 1.66 ng/mL (95% CI, 0.10-3.21) lower for the wet type. Together, the results demonstrated that AMD is associated with elevated tHcy levels and decreased vitamin B12 levels. Plasma tHcy may act as a modulator of the risk for AMD based on the current evidence.
authors.affiliation: 1] Department of Ophthalmology, Shanghai First People's Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China [2] Eye Research Institute of Shanghai Jiao Tong University, Shanghai, China.
authors.forename: Peirong
authors.initials: P
authors.lastname: Huang
authors.affiliation: 1] Department of Ophthalmology, Shanghai First People's Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China [2] Eye Research Institute of Shanghai Jiao Tong University, Shanghai, China.
authors.forename: Fenghua
authors.initials: F
authors.lastname: Wang
authors.affiliation: Department of Surgery, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China.
authors.forename: Birendra Kumar
authors.initials: BK
authors.lastname: Sah
authors.affiliation: Division of Biostatistics, University of Texas Health Science Center, Houston, USA.
authors.forename: Junhai
authors.initials: J
authors.lastname: Jiang
authors.affiliation: Department of Surgery, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China.
authors.forename: Zhentian
authors.initials: Z
authors.lastname: Ni
authors.affiliation: Department of Surgery, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China.
authors.forename: Jentso
authors.initials: J
authors.lastname: Wang
authors.affiliation: 1] Department of Ophthalmology, Shanghai First People's Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China [2] Eye Research Institute of Shanghai Jiao Tong University, Shanghai, China.
authors.forename: Xiaodong
authors.initials: X
authors.lastname: Sun
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D005492:Folic Acid / Q000097:blood; D006710:Homocysteine / Q000097:blood*; D006801:Humans; D008268:Macular Degeneration / Q000097:blood*; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D014805:Vitamin B 12 / Q000097:blood
chemical_list: D006710:Homocysteine; D005492:Folic Acid; D014805:Vitamin B 12