Tobacco use disorder is associated with increased risk of cardiomyopathy in a population-based study from Taiwan.

This population-based, individually matched case-control study aimed to examine the association between tobacco use disorder (TUD) and cardiomyopathy. We conducted a retrospective case-control analysis using data from the 2005 Longitudinal Health Insurance Database, a subset of Taiwan's National Health Insurance Research Database (NHIRD). A total of 10,426 newly diagnosed cardiomyopathy cases and 41,704 matched controls (matched 1:4 by age, sex, and index year) from 2000 to 2015 were identified. TUD exposure was defined using ICD-9-CM codes. Conditional logistic regression was applied to estimate adjusted odds ratios (aORs) and 95% confidence intervals (CIs), adjusting for demographic and clinical covariates. Analyses evaluated both the timing and total duration of TUD exposure preceding cardiomyopathy diagnosis to explore temporal patterns in odds. Prior TUD exposure was associated with higher odds of cardiomyopathy (aOR = 1.376, 95% CI = 1.102-1.598). A recency-related gradient in odds was observed: exposure within < 1 year before diagnosis (aOR = 2.990), 1-5 years (aOR = 1.401), and > 5 years (aOR = 1.126; not significant after Bonferroni correction). A similar duration-related increase in odds was identified: <1 year (aOR = 1.288; not significant after Bonferroni), 1-5 years (aOR = 1.592), and > 5 years (aOR = 2.743). Tobacco use disorder was associated with higher odds of cardiomyopathy, showing both recency-and duration-related gradients in odds. These findings emphasize the importance of early and sustained tobacco cessation to reduce the burden of cardiomyopathy, while acknowledging that causal inference cannot be established due to the case-control design.