Table 1: Characteristics of the included studies investigating seminal plasma zinc concentrations and male infertility.

From: Zinc levels in seminal plasma and their correlation with male infertility: A systematic review and meta-analysis

StudyCountryMean age (cases/controls)CasesZinc supplementationAbstinenceAssaySemen parameters
Türk S 2014Estonia31/3132 NINI 
Fuse H 1999JapanNI14 5AAS 
Colagar AH 2009IranNI15 NIAAS 
Camejo MI 2011Venezuela33.6 ± 9.6/34.3 ± 6.467 3–5XFR 
Hadwan MH 2012IranNI37zinc sulfate 220 mgNIAASSV, STC, SM, SNM
Hadwan MH 2014IranNI60zinc sulfate 220 mgNIAASSV, STC, SM, SNM
Akinloye O 2010Nigeria35 ± 1.2/36.6 ± 1.030 NIAAS 
Haidar M 2013IranNI18zinc sulfate 220 mgNIAASSV, SC, SM, SNM, SPV
Chia SE 2000Singapore34.8 ± 5.3/34.2 ± 4.3107 3AAS 
Wong WY 2002South Africa34.1 ± 4.1/35.3 ± 4.4107zinc sulfate 66 mgNINISV, SC, SM, SNM, SPA
Li Y 2013ChinaNI58NI3–7CCTSM, SPV
Li FB 2008China49.3 ± 2.4/32.6 ± 2.963 3–7AAS 
Liao CS 2011ChinaNI28 5CCT 
Shi KH 2014China29.2 ± 2.9/30.9 ± 3.1154 5AAS 
Wang R 2006ChinaNI119 2–4AAS 
Xu X 1997ChinaNI17 3–5AAS 
Zhang DT 2003ChinaNI876zinc gluconate 10 ml7AASSV, SPV,STC,SPA
Zheng LP 2012ChinaNI265 3–7AAS 
Li P 2012ChinaNI500 3–7AAS 
He Y 2011ChinaNI33 5–7AAS 
  1. Abbreviations: SV, semen volume; SC, sperm concentration (density); SPV, sperm viability; SNM, sperm normal morphology; SPA, sperm abnormal morphology; SM, sperm motility; STC, sperm count; AAS, atomic absorption spectrophotometry; XRF: radionuclide-induced energy dispersive X-ray fluorescence test; CCT, chemical chromatometry test. NI, not indicated in the study.