Peripheral venous blood samples will be drawn on all participants at annual intervals. Samples to assess natriuretic peptides will be drawn into vacutainers containing EDTA and samples to assess renal function, collagen turnover and lipid profile will be collected in vacutainers containing lithium heparin. BNP and Lipid profile assessment will be analysed using point of care meters, Biosite (Triage, USA) and Cholestech respectively. Each of the remaining samples will be centrifuged for 10 minutes and the serum will be then aliquoted and stored at -80°C before analysis of biochemical, genomic, proteomic and metabolomic markers.