High sodium (Na) diet is one of the leading behavioural risks of disease identified in the Singapore Burden of Disease Study. We aim to estimate the cost attributable to a high Na diet in Singapore in 2019 from a societal perspective by employing a prevalence-based approach in cost-of-illness studies. We extracted national-level healthcare data and population attributable fractions by sex and age. Costs included direct and indirect costs from inpatient treatment and productivity losses. In 2019, the annual societal cost attributable to a high Na diet was conservatively estimated to be USA$262 million (95 % uncertainty interval (UI) 218, 359 million). At least USA$67·8 million (95 % UI 48·4, 120 million) and USA$194 million (95 % UI 153, 274 million) could be saved on healthcare and indirect costs, respectively, if the daily Na intake of Singaporeans was reduced to an average of 3 g. Overall, males had higher costs compared with females at USA$221 million (95 % UI 174, 312 million) and USA$41·1 million (95 % UI 33·5, 61·7 million), respectively. Productivity loss from foregone wages due to premature mortality had the largest cost at USA$191 million (95 % UI 150, 271 million). CVD had the largest healthcare expenditure at USA$61·4 million (95 % UI 41·6, 113 million), driven by ischaemic heart disease at USA$41·0 million (95 % UI 21·4, 88·9 million). Our study found that reducing Na intake could reduce future healthcare expenditures and productivity losses. This result is vital for policy evaluation in a rapidly ageing society like Singapore, where the burden of diseases associated with high Na diet is expected to increase.
