|
Age (age at cessation)
|
Mortality (%)a
|
Age corresponding to smokerb
|
|---|
|
Continuing smoker
| | |
|
50
|
0.40
| |
|
55
|
0.95
| |
|
60
|
2.25
| |
|
65
|
5.00
| |
|
70
|
9.65
| |
|
75
|
15.9
| |
|
Former smoker
| | |
|
75 (60)
|
9.9
|
70.22
|
|
75 (50)
|
6.0
|
66.27
|
|
75 (40)
|
3.0
|
61.72
|
|
75 (30)
|
1.7
|
58.37
|
-
aData from Doll et al. [20]
-
bThe corresponding continuing smoker’s age at which cumulative lung cancer mortality risk is equal to the risk of that in former smokers at age 75 was calculated from the quintic equationc which takes account of the risk in continuing smokers. It is a simple technique and not dependent on the cancer model. The difference between age 75 and the corresponding age is considered to be “delayed effect on aging” by cessation of smoking (Fig. 1)
-
c
y = − 1.333333 × 10− 6
x
5 + 3.833333 × 10− 4
x
4 − 0.04306667x
3 + 2.381417x
2 − 65.0675x + 704.4
