Table 1.
Estimated percentage-point changes in mean cigarette consumption per day as a function of e-cigarette use and NRT use among smokers from November 2006 to March 2016, based on ARIMAX models
| All users of nicotine replacement | Only daily users of nicotine replacement | |||||
| Percentage change per 1 % change in the exposure (95% CI) P values | ||||||
| Any current use of e- cigarettes (immediate impact) |
−0.011 (−0.025 to 0.002) 0.097 |
−0.012 (−0.026 to 0.002) 0.091 |
−0.010 (−0.024 to 0.004) 0.149 |
−0.011 (−0.026 to 0.003) 0.130 | ||
| NRT use for harm reduction (immediate impact) |
0.012 (−0.028 to 0.053) 0.546 |
0.015 (−0.026 to 0.055) 0.475 |
0.003 (−0.019 to 0.025) 0.794 | 0.005 (−0.017 to 0.027) 0.672 | ||
| Mass media expenditure (immediate impact) |
<0.001 (−0.001 to 0.001) 0.984 |
<0.001 (−0.001 to 0.001) 0.880 | ||||
| Total percentage change due to the exposure (95% CI) P values | ||||||
| Smoking ban (pulse effect) |
0.015 (−0.070 to 0.101) 0.724 |
0.013 (−0.072 to 0.099) 0.756 | ||||
| Increase in age-of-sale (pulse effect) |
−0.041 (−0.126 to 0.044) 0.342 |
−0.043 (−0.128 to 0.042) 0.324 | ||||
| Move to local authority control (pulse effect) |
−0.019 (−0.105 to 0.067) 0.662 |
−0.027 (−0.112 to 0.058) 0.533 | ||||
| Licensing for NRT for harm reduction (pulse effect) |
0.021 (−0.067 to 0.110) 0.639 |
0.020 (−0.069 to 0.109) 0.661 | ||||
| NICE guidance on harm reduction (pulse effect) |
−0.024 (−0.109 to 0.061) 0.578 |
−0.028 (−0.114 to 0.057) 0.512 | ||||
| Best fitting model | ARIMAX(0,1,1)(0,0,0)12 | ARIMAX(0,1,1)(0,0,0)12 | ARIMAX(0,1,1)(0,0,0)12 | ARIMAX(0,1,1)(0,0,0)12 | ARIMAX(0,1,1)(0,0,0)12 | ARIMAX(0,1,1)(0,0,0)12 |
| Non-seasonal AR p value | NA | NA | NA | NA | NA | NA |
| Non-seasonal MA p value | <0.001 | <0.001 | <0.001 | <0.001 | <0.001 | <0.001 |
| Seasonal AR p value | NA | NA | NA | NA | NA | NA |
| Seasonal MA p value | NA | NA | NA | NA | NA | NA |
| R2 | 0.65 | 0.65 | 0.66 | 0.65 | 0.64 | 0.66 |
| Bayes factor e-cigarette (0.009 (0.1)) | 2.44 (0.46) | 2.68 (0.55) | 1.95 (0.35) | 2.12 (0.41) | ||
| Bayes factor NRT (0.009 (0.1)) | 0.77 (0.14) | 0.74 (0.13) | 0.69 (0.09) | 0.63 (0.08) | ||
An AR(1) means that the value of a series at one point in time is the sum of a fraction of the value of the series at the immediately preceding point in time and an error component; an MA(1) means that the value of a series at one point in time is a function of a fraction of the error component of the series at the immediately preceding point in time and an error component at the current point in time.
AR, autoregressive; ARIMAX, Autoregressive Integrated Moving Average with Exogeneous Input; MA, moving average; NA, not applicable; NICE, National Institute for Health and Care Excellence; NRT, nicotine replacement therapy.