lower for the intervention than for the control group. Although this difference was not statistically significant, it corresponds with an estimated 0.4 life-years gained. From the British Doctors study 1 it is possible to estimate that an intervention that yielded an increased cessation rate at the 12-month follow-up of 30% (39% vs 9%) in smokers with the age distribution represented in this study would be expected to yield approximately 0.8 lifeyears. 9 The Table also shows lower hazard ratios for many specific causes of death in the intervention group compared with the control group, though none were statistically significant at conventional levels. As might be expected, the largest putative effect size was for lung cancer. Comment. Although this study had low power to detect a long-term effect on mortality of the size predicted from the British Doctors study, 1 to our knowledge, these data provide the best estimate of such an intervention to date. This estimated gain of 0.4 lifeyears was approximately half what might be expected from the British Doctors cohort study. 1 In addition to the low sample size, several factors may have militated against showing an effect of the kind predicted. First, there was no biochemical verification of abstinence, so at least some of the "effect" may have resulted from misreporting by smokers in the intervention group who did not want to admit that they were not able to stop. 10 Second, brief advice without pharmacological support tends to lead to cessation in lighter, less nicotinedependent smokers, with heavier smokers requiring more support. 11 These light smokers would have been exposed to less-than-average risk from their smoking.