TABLE 1—

Doll and Peto’s “The Causes of Cancer” and the Changing Sum of Population Attributable Fractions: 1981 vs 1985

	Initial Presentation, 19819(p1256): “Proportions of cancer deaths attributed to various different factors”		Revised Presentation, 198510(p12): “Percentage of all U.S. or U.K. cancer deaths that might be avoidable”
Factor	Best Estimate	Range of Acceptable Estimates	Best Estimate	Range of Acceptable Estimates
Tobacco	30	25–40	30	25–40
Alcohol	3	2–4	3	2–4
Diet	35	10–70	35	10–70
Food additives	< 1	−5–2	< 1	−5–2
Reproductive and sexual behavior	7	1–13	Sexual behavior: 1	1
			Yet-to-be-discovered analogs of reproductive factors: up to 6	0–12
Occupation	4	2–8	4	2–8
Pollution	2	< 1–5	2	1–5
Industrial products	< 1	< 1–2	< 1	< 1–2
Medicines and medical procedures	1	0.5–3	1	0.5–3
Geophysical factors	3	2–4	3	2–4
Infection	10?	1–?	10?	1–?
Unknown	?	?	?	?
			Total: 200 or morea

^aThe 1981 table did not provide a row for “total”; however, the percentages of “best estimates” sum to 97%, not including the unknown “?.” By contrast, the 1985 version of the table stated, “Since once cancer may have two or more causes, the grand total in such a table will probably, when more knowledge is available, greatly exceed 200. (It is merely a coincidence that the suggested figures … happen to add up to about 100.)”¹⁰