Cancer risk factors, exposure variables, theoretical-minimum-risk exposure distributions, disease outcomes*
* New exposure data and epidemiological evidence on disease outcomes and relative risks used when new epidemiological analyses allowed improvements compared with original analyses of Comparative Risk Assessment project—eg, relative risks for site-specific cancers as a result of smoking with better adjustment for potential confounders and new exposure data sources for overweight and obesity.
† Italics=outcomes likely to be causal but not quantified because of insufficient evidence on prevalence or hazard size. Corresponding ICD 9 3-digit codes: bladder cancer 188; breast cancer 174; cervix uteri cancer 180; colorectal cancers 153–154; corpus uteri cancer 179, 182; leukaemia 204–208; liver cancer 155; mouth and oropharynx cancer 140–149; oesophageal cancer 150; pancreatic cancer 157; stomach cancer 151; trachea, bronchus, and lung cancers 162; selected other cancers 210–239. Total deaths from cancer are from WHO. Methods used by WHO32,33 are based on a combination of vital statistics for countries with complete vital registration and medical certification of deaths, and on a combination of demographic techniques and information from cancer registries for countries with incomplete vital statistics, with sample registration or surveillance systems, or without vital registration.
‡ Alcohol has benefits as well as harms for different diseases, also depending on patterns of alcohol consumption. A theoretical minimum of zero was chosen for alcohol use because, despite benefits for specific diseases (cardiovascular) in some populations global and regional burden of disease due to alcohol use was dominated by its effects on neuropsychological diseases and injuries, which are considerably larger than benefits to vascular diseases. Furthermore, no benefits for neoplastic disease have been noted from alcohol.
§ A proportion of HPVinfections that lead to cervix uteri cancer are transmitted through routes other than sexual contact. PAF for unsafe sex, as defined in the comparative risk assessment project,28 measures current population-level cervix cancer mortality that would be reduced, had there never been any sexual transmission of infection—ie, the consequences of past and current exposure, as we do for accumulated hazards of smoking. By considering health consequences of past and current exposure, nearly all of sexually transmitted diseases are attributable to unsafe sex because, in the absence of sexual transmission in the past, current infections transmitted through other forms of contact would not occur if infected hosts acquired their infection sexually (and so on in the sequence of past infected hosts).