Time to first cigarette after waking and incident heart failure: a dose-response analysis from the UK biobank

BACKGROUND AND AIMS: We aimed to investigate the association between time to first cigarette after waking (TTFC) and incident heart failure (HF) in a large prospective cohort. METHODS: This study included 229 391 participants from the UK Biobank. Current smokers were categorized by TTFC intervals (120 min). Multivariable Cox proportional hazards models were employed to assess the relationship between TTFC and HF. Joint analyses evaluated the combined associations of TTFC with daily cigarette amount and smoking duration. Subgroup and interaction analyses were conducted by age, sex, BMI, education, and alcohol consumption. RESULTS: During a median follow-up of 15.5 years, 6912 (3.01%) incident HF cases occurred among 229 391 participants. The cohort included 203 653 (88.77%) non-smokers (age 55.9 ± 8.1 years, 41.4% female, 91.5% White ethnicity, 2.7% incident HF cases) and 25 738 (11.23%) current smokers (age 54.5 ± 8.1 years, 49.0% female, 89.1% White ethnicity, 5.7% incident HF cases). A significant dose-dependent relationship was observed between shorter TTFC and HF risk (P for trend