Characteristics of the nested case-control studies included in this meta-analysis. CaoHongxin WangGuanghui MengLong ShenHongchang FengZhen LiuQi DuJiajun 2013 <p>M,male; F,female; T, storage temperature; RIA, radioimmunoassay assay; IRMA, immunoradiometric assay; ELISA, enzyme-linked immunoabsorbent assay; BMI,body mass index.</p>