Table 1

Parameters for the best fitting segmented regression models of smoking prevalence, ever-smoking prevalence in young adults and quit ratios in Great Britain between 1973 and 2016

Smoking prevalenceEver-smoking prevalence in young adultsQuit ratios
Β95% CIP valueΒ95% CIP valueΒ95% CIP value
Intercept47.54845.95149.144<0.00157.66756.46658.867<0.00125.57322.69828.448<0.001
Time−1.456−1.719−1.193−1.608−1.840−1.376<0.0011.8681.3992.336<0.001
Time2 0 to BP10.0260.0170.035<0.0010.0500.0410.059<0.001−0.039−0.055−0.023<0.001
Time2 BP1 to BP2−0.191−0.345−0.0370.017−0.168−0.196−0.139<0.0010.0590.0230.0950.002
Time2 BP2 to BP30.1670.0090.3420.0620.1400.1030.177<0.0010.5270.0800.9750.023
  • Smoking prevalence, quadratic model with two breakpoints in 2000 (year 27) and 2001 (year 28); ever-smoking prevalence in young adults, quadratic model with two breakpoints in 1994 (year 21) and 2002 (year 29); quit ratio, quadratic model with two breakpoints in 1996 (year 23) and 2013 (year 40).