Abstract P163: Smoking Timing and Hazard of Incident Heart Failure: A Cohort Study in UK Biobank

Objective: Smoking is an establish risk factor for heart failure (HF); however, little is known about how the timing patterns of smoking is related to HF risk. We prospectively evaluated the association of smoking timing with hazard of incident HF; and examined whether smoking intensity or smoking burden might modify the relationship. Methods: This study included 308490 participants from the UK Biobank who were free of HF at baseline and completed the questionnaire on the time from waking to the first cigarette. We evaluated the association between smoking timing and hazard of incident HF using Cox proportional hazards models. Results: During a median follow-up time of 12 years, a total of 6917 incident cases of HF were documented. Compared to non-smokers, the multivariate hazard ratios [95% confidence interval (CI)] of incident HF were 1.47 (1.11-1.95) for >2 hours, 1.74 (1.34-2.25) for 1-2 hours, 2.21 (1.83-2.66) for 30-60 minutes, 2.24 (1.82-2.76) for 5-15 minutes, and 2.39 (1.79-2.19) for <5 minutes of the time from waking to the first cigarette, respectively, independent of smoking intensity or smoking burden ( P for trend <0.001). The positive associations between shorter time from waking to the first cigarette and hazard of incident HF were more pronounced in female participants than in male participants ( P -interaction=0.001). We found that even among participants with light smoking intensity, those with the shortest time from waking to the first cigarette had a 178% or a 261% higher risk of HF (HR 2.78, 95% CI 1.92-4.03), comparable to that among people with heavy smoking intensity or heavy smoking burden, respectively. Conclusions: Our findings indicate that shorter time from waking to the first cigarette is significantly associated with a higher hazard of incident HF, independent of smoking intensity or smoking burden.