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Cancer Risk Factors

Cancer is more often caused by the environment a person lives in, rather than his or her innate biology.

Cancer incidence age-standardized rates (world) per 100,000, circa 1970

Risks of Tobacco

Preventable deaths: a substantial proportion of cancer deaths are caused by tobacco, especially among men.

Cancer deaths (in millions) attributable to tobacco, 2010

Chart showing cancer deaths (in millions) attributable to tobacco in 2010 which indicates that a substantial proportion of cancer deaths are caused by tobacco, especially among men

Infection

Many of the most common cancers are at least partly attributable to infection.

Percentage of new cancer cases caused by infection and total number of new cases

Chart showing the percentage of new cancer cases caused by infection and total number of new cases which indicates that many of the most common cancers are at least partly attributable to infection

Diet, Body Mass, and Physical Activity

For some cancer sites, excess body weight accounts for a large proportion of cases.

Percentage of new cancer cases in high-income countries caused by excess body weight

Illustration that shows the percentage of new cancer cases in high-income countries caused by excess body weight

Ultraviolet Radiation

In some countries, melanoma rates continue to increase among older males while rates among younger males show signs of decreasing.

Trends in age-standardized incidence rate (world) per 100,000 population, 1955-2000

Graph showing trends in age-standardized incidence rate of melanoma per 100,000 population, 1955-2000 which indicates that in some countries, melanoma rates continue to increase among older males while rates among younger males show signs of decreasing

Reproductive and Hormonal Factors

Breastfeeding and childbearing reduce the risk of breast cancer among women, whereas oral contraceptive use and hormone replacement therapy increase the risk.

Hormonal and reproductive risk factors for breast cancer

Images with statistics and information that indicate that breastfeeding and childbearing reduce the risk of breast cancer among women, whereas oral contraceptive use and hormone replacement therapy increase the risk

Environmental Pollutants and Occupational Exposures

Asbestos consumption has dramatically declined in many countries, but has remained the same or increased in some fast-growing economies.

Asbestos consumption in selected countries/regions, 1970 vs. 2003

Bar chart showing asbestos consumption in selected countries/regions, 1970 vs. 2003 which indicates that asbestos consumption has dramatically declined in many countries, but has remained the same or increased in some fast-growing economies (such as China, Brazil, India)

Human Carcinogens Identified by the IARC Monographs Program