Table 2.

Smoking status versus cumulative risk of death from lung cancer by age 75, from 1950 and 1990 studies

Smoking status	Men						Women
	% of cases/controls			Cumulative risk (%)			% of cases/controls			Cumulative risk (%)
	1950	1990		1950*	1990		1950	1990		1950*	1990
Lifelong non-smoker	0.5/4.5	0.5/19.0		∼0.4	∼0.4		37.0/54.6	7.6/50.3		∼0.4	∼0.4
Former smokers	5.2/9.1	42.7/52.5		2.9	5.5		9.3/7.4	29.8/29.4		0.9	2.6
Current pipe or cigar only	3.9/7.2	8.5†/7.1		2.8	8.1†		0/0	0.6/0.1		—	—
Current cigarette smokers	90.4/79.2	48.3/21.5		5.9	15.9		53.7/38.0	61.9/20.1		1.0	9.5
Amount smoked (% of smokers)‡
<5/day	3.6/7.0	6.2§/9.5		2.8	10.4§		20.6/36.7	4.1§/10.1		0.6	3.4§
5-14/day	38.2/47.5	33.5/39.7		4.4	12.8		44.1/44.9	32.3/37.8		1.0	7.7
15-24/day	33.0/31.5	39.1/37.3		5.7	16.7		35.3/18.4**	44.1/42.4		2.0**	10.4
⩾25/day	25.2/14.0	21.1/13.5		9.8	24.4			19.5/9.7			18.5
Total	100/100	100/100					100/100	100/100
No of cases	1357/1357	667/2108		—	—		108/108	315/1077		—	—

^*The cumulative risk by age 75 in 1950 was estimated for smokers and former smokers by multiplying the published relative risks⁷ by 0.6 for men and 0.5 for women. This, together with the population prevalences, yields the cumulative risks of 4.7% for men and 0.7% for women seen in 1950 UK national statistics (see BMJ's website). That for lifelong smokers in 1950 and 1990 was estimated from a US prospective study. 

^†The effects of smoking only pipes or cigars cannot be assessed here, as 88% of these cases had previously smoked cigarettes. 

^‡By tobacco most recently smoked (1950 study, taking 1 g of other tobacco as one cigarette) or by current cigarettes (1990 study). 

^§The effects of <5 cigarettes a day cannot be assessed here, as 93% of these cases had previously smoked over 15 a day and several had smoked over 30. 

^**Women in 1950 study who smoked ⩾15 cigarettes a day.