Effect of continuous smoking reduction and abstinence on blood pressure and heart rate in smokers switching to electronic cigarettes

Abstract

We present prospective blood pressure (BP) and hear rate (HR) changes in smokers invited to switch to e-cigarettes in the ECLAT study. BP and HR changes were compared among (1) different study groups (users of high, low, and zero nicotine products) and (2) pooled continuous smoking phenotype classification (same phenotype from week 12 to -52), with participants classified as quitters (completely quit smoking), reducers (≥50% reduction in smoking consumption) and failures (<50% or no reduction in smoking consumption). Additionally, the latter comparison was repeated in a subgroup of participants with elevated BP at baseline. No significant changes were observed among study groups for systolic BP, diastolic BP, and HR. In 145 subjects with a continuous smoking phenotype, we observed lower systolic BP at week 52 compared to baseline but no effect of smoking phenotype classification. When the same analysis was repeated in 66 subjects with elevated BP at baseline, a substantial reduction in systolic BP was observed at week 52 compared to baseline (132.4 ± 12.0 vs. 141.2 ± 10.5 mmHg, p < 0.001), with a significant effect found for smoking phenotype classification. After adjusting for weight change, gender and age, reduction in systolic BP from baseline at week 52 remains associated significantly with both smoking reduction and smoking abstinence. In conclusion, smokers who reduce or quit smoking by switching to e-cigarettes may lower their systolic BP in the long term, and this reduction is apparent in smokers with elevated BP. The current study adds to the evidence that quitting smoking with the use of e-cigarettes does not lead to higher BP values, and this is independently observed whether e-cigarettes are regularly used or not.

Keywords: Blood pressure; Electronic cigarette; Heart rate; Smoking cessation; Smoking reduction; Tobacco harm reduction.

Fig. 1

Schematic diagram of the ECLAT study design. Smokers not currently attempting to quit smoking or wishing to do so in the next 30 days were randomised in three study groups: group A (receiving 12 weeks of 2.4 % “Original” nicotine cartridges), group B (receiving 6 weeks of 2.4 % “Original” nicotine cartridges and a further 6 weeks with 1.8 % “Categoria” nicotine cartridges), and group C (receiving 12 weeks of no-nicotine “Original” cartridges). Participants in each group were prospectively reviewed for up to 52 weeks during which smoking habits, eCO levels, BP, HR and body weight were assessed at each study visits

Fig. 2

Time course of systolic blood pressure, diastolic blood pressure, and heart rate (in % of baseline) for each step (means and 95 % CI) separately for study groups (A, B, and C). Within subjects changes were significant (p = 0.004) only for SBP, while no between subject effect (Group) was found (repeated measures ANOVA)

Fig. 3

Changes (mean ± SD, absolute mmHg) in systolic blood pressure (SBP) from baseline to week 52 for continuous smoking phenotypes, separately for subjects with normal and elevated SBP at baseline. P values for statistical significance of changes from baseline are shown