FS participated in the design of the study, read all interview transcripts, performed the coding schemes and analysis, interpreted the data, commented on the drafts of the manuscript.
JS, AK, MR and FD assisted in study design and in interpreting the data and commented on the manuscript.
WBG performed data analysis and interpreted the data and results.
SG was involved in designing and writing the study protocol, analysed and interpreted the data and made comments on the draft of the manuscript.
SG was involved in the designing of the study protocol, interpreted the data, and made comments to the first and second drafts of the manuscript.
JK was involved in the designing of the study protocol, supervised the study, interpreted the data, and made comments to the first and second drafts of the manuscript.
JG obtained the funding, prepared the samples, supervised the study, interpreted the data, and made critical comments on the manuscript.
XPZ and SLM interpreted the data and performed analysis.
CE contributed to the design, assessed literature, conducted data entry, analysis, interpreted data and commented on drafts of the paper.
