Table 4 Papers excluded from the meta-analysis

Nwokolo et al, 2003[2]

Reported median values & 95% CI; also measured integrated ghrelin levels rather than the discrete measurement that other authors used. The authors stated that the median values were used because the sample size was small and the data were skewed

Mendez-Sanchez et al, 2007 [49]

Studied ghrelin immuno-reactive cells, did not provide data on plasma ghrelin levels

Salles et al, 2006[19]

Ghrelin values not provided. Only P-values

Gao et al, 2009[15]

Ghrelin values not provided

Choe et al, 2007[6]

Median & IQR provided. Further clarifications not provided by the authors

Czesnikiewicz-Guzik et al, 2005[12]

Insufficient information for meta-analysis

Czesnikiewicz-Guzik et al, 2007 [13]

Insufficient information for meta-analysis

Masaoka et al [51]

This was a case study with only one subject

Stec-Michalska et al, 2009[24]

Measured only gastric ghrelin

Liew et al, 2006[47]

Assessed only gastric ghrelin

Konturek et al, 2006[17]

The numbers of H pylori positive and negative participants were not provided and the authors did not respond to requests for further information.