Quitting smoking at any age yields mortality benefit
Medwire News: The sooner smokers quit the better, but even octogenarians can reduce their risk of death when they kick the habit, German investigators report.
A systematic review of 17 studies revealed that current smokers aged 80 years and older had a 1.7-fold increased relative mortality risk compared with never smokers, whereas former smokers in the same age group had a 1.3-fold increased risk.
"The longer the time since smoking cessation, the lower the relative mortality of older former smokers; this fact calls for effective smoking cessation programs that are likely to have major preventive effects even for smokers aged 60 years and older," report Hermann Brenner (German Cancer Research Center, Heidelberg) and colleagues in the Archives of Internal Medicine.
The authors combed through the medical literature looking for cohort studies with data on the association between smoking and all-cause mortality in people 60 years and older.
They found that current smokers were at increased risk for all-cause mortality in all of the studies, with relative mortality in the individual studies ranging from 1.2 to 3.4 compared with never smokers. In a meta-analysis of data from all of the studies, the relative mortality for current smokers was 1.8.
With increasing age, there was a decline in the difference between current and never smokers, but the decrement for current smokers never disappeared.
"One plausible explanation can be the 'depletion of susceptibles' effect," Brenner et al write. "Smokers who are still alive at oldest age might be less likely to die from smoking because they showed a tolerance for harmful smoking effects in the past, while smokers who were more susceptible to harmful smoking effects have died already at younger age and dropped out of the population at risk."
Alternatively, the difference between older current and never smokers might blend into the background of a sharp increase in absolute mortality that occurs among people older than 70, the authors suggest.
By Neil Osterweil