It seems like every week someone else is telling us that something or the other is bad for us or causes cancer, but just how much of this is really true?
Are mobile phones really bad for you; do microwaves cause cancer; do Electric and Magnetic Fields (EMFs) cause cancer; does Teflon cookware cause cancer, and is the Medical Industry really hiding a Cure for Cancer to make $$$? Find the answers to these questions and others in this article.
Several dozen studies have looked at the possible links between mobile phone use and tumours. These studies have consistently found that there is no increased incidence of brain tumours in mobile phone users compared to non-mobile phone users; that there is little evidence of risk of brain tumour being higher with increasing mobile phone use; and that most studies do not show that brain tumours occur more often on the side of the head where people hold their mobile phone. The few studies that have found a possible link have all been conducted by the same research group and have not been replicated by other scientists.
Theoretically, children are at greater potential risk than adults for developing brain cancer related to mobile phone use, as they are still developing physically and therefore may be more vulnerable to factors that may lead to cancer. To date, however, the evidence from studies on mobile phone use in children does not support this theory. The first published evidence comes from a large European study called CEFALO, which included children aged 7 to 19, who were diagnosed with brain tumours. The study did not find an association between mobile phone use and brain tumour risk in this group of children.
In 2002, the International Agency for Research on Cancer (IARC) reviewed the available evidence in relation to extremely low frequency magnetic fields and cancer. Based on the weak association between extremely low frequency magnetic fields and childhood leukaemia found in epidemiological studies, inadequate human data for all other cancers, and inadequate animal data, IARC classified extremely low frequency magnetic fields as a possible human carcinogen.
In 2007, the World Health Organization (WHO) reviewed the evidence, focusing on studies published after the IARC review. WHO concluded that the results of relevant research published since 2002 did not warrant a change in the classification of extremely low frequency magnetic fields as a possible human carcinogen.
Most recently, in February 2014, research by the Childhood Cancer Research Group at the University of Oxford was published in the British Journal of Cancer. The study analysed data from the National Registry of Childhood Tumours, including 16,500 children who developed leukaemia in Britain between 1962 and 2008. The researchers found that although there was a higher risk of developing leukaemia among those who lived within 600 metres of power lines in the 1960s and 1970s, the risk declined over time and from the 1980s onwards, there has been no increased leukaemia risk among those living near power lines. The researchers concluded that children who live near overhead power lines do not have an increased risk of developing leukaemia; but the reasons for the declined risk over time are not clear, and continued research is required to understand the historical patterns.
Microwave ovens do not make foods radioactive. Microwave ovens heat food by producing radiation which is absorbed by water molecules in the food. This makes the water molecules vibrate and produce heat, which cooks the food. Microwaves heat food. They do not make any changes to food that aren’t made in any other cooking method. So they do not make food any more likely to cause cancer. If you follow the instructions for use for a microwave oven there is no known harmful effect on humans. For more information on radiation emissions from microwave ovens please refer to the Australian Radiation Protection and Nuclear Safety Agency website.
Teflon is a brand name for the man-made chemical polytetrafluorothylene (PTFE). Perfluorooctanoic acid (PFOA) is another man-made chemical that is used in the process of making Teflon, although it is burned off during the process and is not present in large quantities in the final product. Teflon itself is not suspected to cause cancer.
The concern regarding Teflon and cancer risk is around the fumes released when Teflon is used for cooking. According to the Australian Government’s National Industrial Chemicals Notification and Assessment Scheme (NICNAS), fumes are only released from Teflon-coated cookware when it is heated to extremely high temperatures (340°C-650°C); temperatures so high they would incinerate your food. There is no evidence that fumes are released from cookware at or below normal cooking temperatures. It is however advisable not to overheat an empty non-stick pan or to leave it unattended on the stove, particularly at a high setting.
The conspiracy theory that the medical industry is hiding a cure for cancer from the public has been around for many years. Logical arguments against this myth include the fact that many people in the scientific and medical industry, such as researchers, nurses, and doctors along with their families and friends, die of cancer at similar rates as everyone else in the population.
Finding one cure for cancer is unlikely because there are more than 200 different kinds of cancer, each with its own underlying genetic faults and correspondingly, its own most appropriate treatment. The survival rate for many common cancers has increased by more than 30 per cent in the past two decades.
The relationship between lung cancer and exposure to diesel exhaust outside of the workplace has not been studied extensively. Measures can be taken to reduce individual and occupational exposure to diesel exhaust. Cancer Council NSW agrees with the conclusion of other reputable cancer organisations, including Cancer Research UK, that diesel exhaust does cause cancer, but the overall risk to the general population is low compared to other risk factors such as tobacco, excess bodyweight, and alcohol.
Emissions from diesel engines are a mix of gaseous compounds and particulate matter. Gaseous compounds include carbon dioxide, water vapour, oxygen, sulphur and nitrogen compounds, carbon monoxide, and low molecular weight hydrocarbons and their derivatives. Particulate matter can contain elemental carbon, organic compounds (including Polycyclic aromatic hydrocarbons, a number of which are known or suspected carcinogens (cancer causing substances)), metals, and other trace compounds. These particles are a public health concern due to their small size (Particulate Matter of ~10 micrometers or less [PM10]) which makes them easy to inhale and able to reach the deep lung.
In June 2012, the International Agency for Research on Cancer (IARC) updated the diesel engine exhaust classification from probably carcinogenic to humans (Group 2A) to carcinogenic to humans (Group 1). IARC is a part of the World Health Organisation which convenes international expert working groups to evaluate the evidence of the carcinogenicity of specific exposures. This category is used when there is sufficient evidence of carcinogenicity in humans. This IARC classification indicates that diesel exhaust damages the DNA, or genetic material, in body cells in a way that leads to cancer, and that this happens in humans. However this classification does not indicate the extent of exposure required to cause this DNA damage, or the significance of the problem for the general population.
The IARC classification of diesel exhaust is based on ‘in vitro’ (studies of cells in laboratory settings), animal and human studies. Studies conducted of cells in laboratory settings such as Petri dishes have shown that diesel exhaust can cause changes in the DNA of those cells. These types of changes are usually necessary for cancer to develop, although not all substances that cause DNA changes also cause cancer.
Animal studies have demonstrated that tumours can develop when diesel exhaust particulate is either applied to the skin or administered internally. A number of studies conducted among laboratory animals such as rats have also shown that long-term inhalation of high concentrations of diesel engine exhaust causes lung cancer in these animals.
Exposure to diesel exhaust is part of everyday life for many Australians. In busy urban areas, exposure to low levels and short-term peak levels of diesel exhaust are often unavoidable. People are exposed to diesel exhaust mainly as a result of inhaling the particles and gases, which then enter the lungs. People may be exposed to diesel exhaust at work, at home, or while traveling; and the amount of diesel exhaust to which individuals may be exposed varies. The main challenges in studying the possible health effects of diesel exhaust among people include: difficulty in defining and measuring the level of exposure, as diesel exhaust is chemically complex and many parts of it are also found in other sources; and difficulty in separating out the impact of other cancer risk factors, such as cigarette smoking.
Lung cancer is the major cancer thought to be linked to diesel exhaust. Most of the recent evidence comes from studies looking at cancer rates among populations that have high levels of exposure to diesel exhaust. Several studies of workers exposed to diesel exhaust have shown small but significant increases in risk of lung cancer. Men with the heaviest and most prolonged exposures, such as railroad workers, heavy equipment operators, miners, and truck drivers, have higher rates of death from lung cancer than men who are not exposed to diesel exhaust fumes as a result of their occupation.
The IARC decision to upgrade diesel exhaust from probably carcinogenic to humans (Group 2A) to carcinogenic to humans (Group 1) followed two papers arising from the Diesel Exhaust in Miners study which were published in the first half of 2012 in the Journal of the National Cancer Institute. This study looked at exposure levels and cancer rates in a population of more than 12,000 miners at eight non-metal mines in the US, and found substantially higher lung cancer rates among those with the highest exposure. The full cohort results showed significant increases in the risk of lung cancer mortality among underground workers as the level of diesel exposure increased, especially among those who had been employed in the mines for more than five years. This nested case-control study, in which miners who died from lung cancer were compared with matched control miners who did not die from lung cancer, showed that, after taking smoking and other lung cancer risk factors into account, miners with heavy exposure to diesel exhaust were three times more likely to die from lung cancer than miners with the lowest exposures.
We will bust some more interesting Cancer-Causing Myths on this blog in the near future, so please keep a look-out.