BACKGROUND: It is necessary to explore the health problems of vulnerable workers who experience repeated unemployment spells. The number of unemployment spells should be considered in the relationship between unemployment and cardiovascular disease (CVD) mortality. Using nationwide data, we aimed to investigate the relationship between unemployment and CVD mortality and examine whether this effect varies depending on the number of unemployment spells. METHODS: Using data from Statistics Korea and employment insurance databases from 2018 to 2019, we identified an average of 1387 CVD deaths per year among 7.76 million workers who had at least one employment record prior to their death. The number of unemployment spells was calculated based on the employment history over the past 5 years. Crude mortality rates per 100 000 individuals and age-standardised mortality rates (SMRs) and sex-SMRs were calculated. RESULTS: The crude mortality rate due to CVD was 17.9 per 100 000 individuals among workers. Workers with one unemployment spell in the past 5 years had a significantly higher SMR than those without (2.01
95% CI 1.87 to 2.16). Additionally, as unemployment spells increased, the SMR increased. The impact was more substantial among older workers than among younger workers. These findings remained consistent when CVD was divided into ischaemic heart disease and cerebrovascular disease. CONCLUSION: Repeated unemployment spells may be a risk factor for increased CVD mortality. These findings underscore the vulnerability of individuals facing repeated unemployment spells, highlighting the necessity for economic as well as health and psychological support.