Lifestyle phenotypes associated with sudden cardiac arrest in the community: a multicentre case-control study

AIMS: Sudden cardiac arrest (SCA) often occurs in individuals without diagnosed cardiovascular disease, suggesting conventional risk assessment may overlook behavioural contexts. We examined whether co-occurring lifestyle behaviours formed distinct phenotypes associated with SCA. METHODS: We analysed data from a prospective multicentre case-control study conducted in South Korea (2017-2023) including out-of-hospital cardiac arrest of presumed cardiac aetiology and community controls frequency-matched by age, sex, and residential area. Seven lifestyle indicators were assessed: smoking, physical activity, sleep duration, and intake of red meat, fish, fruit, and vegetables. Latent class analysis identified lifestyle phenotypes, and odds ratios (ORs) were estimated using a single fully adjusted logistic regression model informed by a directed acyclic graph. RESULTS: The primary analysis included 1,466 cases and 2,619 controls, identifying five phenotypes. The reference class (C2) showed the lowest observed proportion of SCA and a predominantly middle-frequency dietary pattern. Compared with C2, fully adjusted odds of SCA were higher for C1 (OR, 1.48; 95% confidence interval: 1.13-1.94) and C3 (1.95; 1.60-2.39), and markedly higher for C4 (8.93; 6.75-11.81) and C5 (15.20; 11.19-20.64). C5 was characterised by high reported intake frequency across food groups, particularly red meat and fish; C4 combined current smoking, physical inactivity, and inadequate sleep with low reported intake frequency across food groups. CONCLUSION: Cluster-derived lifestyle phenotypes were associated with differing odds of SCA. Although causal effects and absolute risk cannot be inferred from this case-control design, these multidomain patterns may help characterise behavioural profiles associated with SCA and inform future prevention research.