1 Department of Endocrinology, Prince Charles Hospital, Cwm Taf University Health Board, Merthyr Tydfil, Mid Glamorgan, UK.
2 Department of Clinical Biochemistry, Prince Charles Hospital, Cwm Taf University Health Board, Merthyr Tydfil, Mid Glamorgan, UK Faculty of Life Sciences and Education, University of South Wales, Pontypridd, UK.