Doctors are concluding that the majority of discovered cancers are attributable to preventable lifestyle practices. Cigarette smoking is believed to account for one third of all deaths by cancer similarly dietary practices also account for the same proportion of cancer deaths. More than any other food product the consumption of red meat has been accused of contributing to the development of cancers. Researchers, however, do not completely support this position and contend that “the associations between meat consumption and cancer risk are not consistent.
” Other uncontrollable factors that may lead to the development of cancer are the presence of viruses such as hepatitis, papilloma and Epstein-Barr viruses are the most notable. In addition the bacterium Helicobacter pylori has also been associated with the development of certain cancers. Cancers attributed to these sources account for approximately 15% of cases. Viswanath et al also suggest that there is a link between an individual’s socioeconomic status and their risk of developing cancer.
They account for this by arguing that high and low SES have differentiated access to both information and proper health care and are thus very unlikely to be aware of the cancer risks they expose themselves to. Further environmental factors particularly with regard to exposure to pollutants have also been blamed for an estimated 5% of cancers. The World Health Organization has long established that environmental factors significantly determine the development of cancers.
Of course there are also other hereditary and genetic factors that contribute to the development of cancer cells. Cancer is also classified as a genetic disease. This means abnormalities in cells can often be attributed to pre-existing mutations. Researchers, however, though acknowledging this genetic link to the development of cancer, are still not certain as to how genetic mutations occur or the ways in which they put individuals at greater risk. Some culturally specific practices may put certain ethnicities at a particular risk or protection from developing types of cancers.
Eisenbud points out, for example, that betel nut chewers in Southeast Asia are at greater risk of developing cancer of the mouth while the practice of circumcision among Jews and Muslims decreases their risks of developing cancer of the penis. Steen proposes that “Of the top 25 completely preventable causes of cancer in the United States, about 84% are lifestyle-related. ” Viswanath et al also present that between a third and a half of all cancers that develop are preventable.
This simply means that, aside from having cancer genes passed on through heredity, there is much that persons can do to decrease their risks of developing cancer. In listing the top 25 preventable causes of cancer Steen puts Hepatitis B virus infection at the top followed by long-term tobacco smoking, the HPV virus, high fat intake, low folate intake, high alcoholic consumption, DDT exposure, consumption of red meat, Helicobacter infection and highly stressful life events. These make up the top ten in that order.
These elements individually contribute to high rates of particular cancers but more specifically liver, lung, cervical, oropharyngeal, breast, colon and stomach cancers. Danaei et al analyze a wide array of literature and identified nine behavioral and environmental risk factors that are prevalent and which are argued to contribute to the development of cancer. Table 1 gives an overview of some known cancer types along with figures of the amount of deaths over a five year period up to 2001.
Total deaths are further broken down according to the behavioral or environment factor that was indicated to have led to the disease. Both percentages and total numbers are given. From that data it is evident that smoking and alcohol consumption are two of the most important behavioral factors that contribute to the development of cancer. In most of the cancer categories smoking represented the largest contributing factor and where smoking was not prominent alcohol consumption was at the head of the list.
According to this data smoking accounted for 70% of deaths from trachea, bronchus and lung cancers, 42% of oropharynx and oesophageal cancers, 28% of bladder cancers and 14% of liver cancers. Similarly alcohol consumption accounted for 26% of oesophageal cancers and 16% of mouth and oropharynx cancers. Adapted from G Danaei et al, ‘Causes of cancer in the world: Comparative risk assessment of nine behavioural and environmental risk factors’, Lancet, vol. 366, 2005, p. 1787.