The overarching hypothesis of this study is that the kidney and the skin form an integrative network for water conservation, where Na+ storage is utilized to prevent body water loss, even at the expense of increased cardiovascular risk. The aim of this project is to characterise skin and muscle Na+ storage in a cohort designed to prospectively measure cardiovascular outcomes in Singaporeans, in order to determine whether humans with increased tissue Na+ storage have increased cardiovascular risk. To gain a better understanding of the mechanisms behind Na+ storage, the investigators will also test the hypothesis that participants with mutations of the skin protein filaggrin, who have increased water loss through the skin, will have increased skin Na+ storage and higher blood pressure levels.