Objective: To evaluate the effect of antidepressant use on lung cancer risk.
Methods: We conducted a case-control study nested in a cohort of patients 40-84 year-old in 1995-2004, without a prior diagnosis of cancer using The Health Improvement Network (THIN) database in the UK. Cases comprised 4,336 patients with a first diagnosis of primary lung cancer. A sample of 10,000 controls was frequency-matched to the cases for age, sex, and the calendar year of diagnosis. The index date for exposure definition was one year before the diagnosis for cases and one year before a random date for controls. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using conditional logistic regression models adjusted for potential confounders.
Results: Selective serotonin reuptake inhibitor (SSRI) use during the year preceding the index date with treatment duration of at least one year had an OR of 0.59 (95% CI 0.41, 0.86). The corresponding OR was 1.23 (95% CI 0.96, 1.58) for tricyclic antidepressants (TCAs).
Conclusions: SSRI use did not increase the lung cancer risk and might be associated with a reduced risk. However, residual confounding might explain the apparent protective effect found for SSRI use, as well as the marginally elevated risk observed among TCA users.