• 08 MAY 16
    • 0

    Commentaries: Prof Simon Chapman finds no link between mobile phone use and brain cancer. Good epidemiology or spin?

    From the Chapman paper, published in Cancer Epidemiology:

    Has the incidence of brain cancer risen in Australia since the introduction of mobile phones 29 years ago?
    Simon Chapmana,*, Lamiae Azizia, Qingwei Luoa,b, Freddy Sitasa,c
    a School of Public Health, University of Sydney, Australia
    b Cancer Council NSW, Sydney, Australia
    c School of Public Health and Community Medicine, University of New South Wales, Australia
    Accepted 19 April 2016

    Abstract

    Background: Mobile phone use in Australia has increased rapidly since its introduction in 1987 with
    whole population usage being 94% by 2014. We explored the popularly hypothesised association between
    brain cancer incidence and mobile phone use.
    Study methods: Using national cancer registration data, we examined age and gender specific incidence
    rates of 19,858 male and 14,222 females diagnosed with brain cancer in Australia between 1982 and 2012,
    and mobile phone usage data from 1987 to 2012. We modelled expected age specific rates (20 39, 40 59,
    60 69, 70 84 years), based on published reports of relative risks (RR) of 1.5 in ever users of mobile
    phones, and RR of 2.5 in a proportion of ‘heavy users’ (19% of all users), assuming a 10 year lag period
    between use and incidence.
    Summary answers: Age adjusted brain cancer incidence rates (20 84 years, per 100,000) have risen
    slightly in males (p < 0.05) but were stable over 30 years in females (p > 0.05) and are higher in males 8.7
    (CI 8.1 9.3) than in females, 5.8 (CI 5.3 6.3). Assuming a causal RR of 1.5 and 10 year lag period, the
    expected incidence rate in males in 2012 would be 11.7 (11 12.4) and in females 7.7 (CI 7.2 8.3), both
    p < 0.01; 1434 cases observed in 2012, vs. 1867 expected. Significant increases in brain cancer incidence were observed (in keeping with modelled rates) only in those aged 70 years (both sexes), but the increase in incidence in this age group began from 1982, before the introduction of mobile phones. Modelled expected incidence rates were higher in all age groups in comparison to what was observed. Assuming a causal RR of 2.5 among ‘heavy users’ gave 2038 expected cases in all age groups. Limitations: This is an ecological trends analysis, with no data on individual mobile phone use and outcome. What this study adds: The observed stability of brain cancer incidence in Australia between 1982 and 2012 in all age groups except in those over 70 years compared to increasing modelled expected estimates, suggests that the observed increases in brain cancer incidence in the older age group are unlikely to be related to mobile phone use. Rather, we hypothesize that the observed increases in brain cancer incidence in Australia are related to the advent of improved diagnostic procedures when computed tomography and related imaging technologies were introduced in the early 1980s.

    SNIP

    NOTE: in 2013 The Australian Skeptics awarded their Skeptic of the Year award to Professor Simon Chapman.

    The Skeptic of the Year award goes to the individual or group that has done the most for skepticism in Australia during the last year. He is of the opinion that current concerns about electromagnetic fields as merely a form of “technophobic” anxiety about modern technology.Thus his scientific opinions can be considered as having a strong intellectual bias in favour of skepticism. No surprise that his views are frequently quoted by the Australian Mobile Telecommunications Association (AMTA).

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    Comments

    I From Lloyd Morgan, the Environmental Health Trust:

    Chapman uses a classic technique of obfuscation. Instead of examining the annual percent incidence change per year of brain cancers located in the anatomical regions of the brain that absorb almost all of the radiation, and incidence among the brain cancers with the highest risk of brain cancer from cellphone use: glioblastoma multiforme (GBM) he switches the topic from annual percent change (APC) to a “what if” relative risk approach. SWITCH THE TOPIC, LOSE THE PICTURE

    This “what if” approach has many false assumptions:
    1. All regions of the brain are equally at risk. NOT TRUE.
    a. Almost all the absorbed radiation is on the side of head where the cellphone is place to the ear and is in the frontal lobe, temporal lobe and cerebellum.
    b. Zada et al’s analysis of California Cancer Registry APCs in these 3 regions are (from Table 3):
    i. frontal lobe, APC=2.4%, p<0.001 (99.9% confidence);
    ii. temporal lobe, APC=1.9%, p=0.026 (97% confidence), and;
    iii. cerebellum, APC=11.9%, p<0.001 (99.9% confidence.
    Because there are two lobes (left & write) these APCs would be about double if we knew which side of the head the cellphone was held.

    2. The entire population was cellphone users from 1987 to 2014. NOT TRUE.
    a. Chapman paper’s Fig. 1, “Percentage of Australians with mobile phone accounts.
    i. Seven year after firs use, in 1993 only about 10% had cellphone accounts
    1. No information is provided about the average hours of use
    a. Did the authors ask ACMA if they had this data?
    ii. Ten year after first use in 1996 about 20% had cellphone accounts (see 1.& a., above
    iii. It was not until 2001 (15 years after first use) that >50% had cellphone accounts (15 of the 29 years in Fig. 1).
    iv. Fig. 1 shows data for every year but there was NO DATA for 10 of these 15 years (1978-1990, 1992-1997) but the missing data were “estimated by linear interpolation.”
    3. All ages use cellphones equally. NOT TRUE.
    4. Both genders use cellphones equally. NOT TRUE.

    SWITCH THE TOPIC LOSE THE PICTURE

    In addition the Summary answers: section contradicts itself. “Age adjusted brain cancer incidence rates (20–84 years, per 100,000) have risen slightly in males (p < 0.05) ….” This sentence is contradicted several sentences later, “Significant increases in brain cancer incidence were observed … only in those aged ≥70 years ….” The value of “slightly’ is not stated but it was a statistically significant increase. The source of funding is not mention. Absence of funding information is a red flag. Best regards, Lloyd Morgan *****************************************************************************************************

    II From Katherine Smith, Natural Medicine NZ:

    Do you really think that mobile phones DON’T increase the risk of brain cancer?

    by Katherine Smith | 7 May, 2016 | Cancer Prevention and Treatment, Environmental Health, News |

    A new study by Professor Simon Chapman et al which was published by Cancer Epidemiology has just been trumpeted in The Conversation and the Daily Mail as showing that cell phones don’t cause brain cancer.

    But is this really the case?
    The text of abstract alone gives rise to some observations and pertinent questions:

    Why was 10 years chosen for a cut off point for the Chapman study?

    The new Chapman study was designed to detect a 50% increase in incidence in brain cancer assuming that this excess risk should show up at 10 years of cellular phone use.

    By comparison, world renowned Australian neurosurgeon Charlie Teo (whose surgical skill has saved or extended the lives of many brain tumour patients) has been quoted (in 2008 as saying: “If you look at the science on mobile phones and the link with brain cancer, it is quite compelling … we know that [ionising] radiation causes cancer, but it takes about ten years for it to develop, so we know that electromagnetic radiation [from phones] is going to take at least ten years to create brain tumours and possibly longer fifteen, twenty years.” [emphasis added]

    Moreover, a major study by Lennart Hardell and Michael Carlberg published in 2014, showed a significant increase in glioma (a common, and unfortunately often fatal, type of brain tumour) for people who used both mobile and cordless phones.

    The 2014 study (published in the journal Pathophysiology) showed that the brain tumour risk was highest after 25 years of mobile phone use and after 15-20 years of cordless phone use.

    See: https://lennarthardellenglish.wordpress.com/2014/12/01/new-study-confirms-increased-risk-for-glioma-associated-with-use-of-mobile-phones-and-cordless-phones

    According to the Chapman study, mobile phones were introduced into Australia 29 years ago. Given that the Hardell study shows that it takes 25 years (or more) exposure for the maximum increase in cell phone-related brain cancers to be detected, it is perhaps not surprising that the 2016 Chapman study did not find a significant excess risk.

    According to the Chapman study abstract, cell phones were introduced into Australia in 1987 (only 29 year ago). While today over 90% of Australians are estimated to use a cell phone, at the time of the introduction of this technology to the country in 1987, only a small minority of people actually used a cell phone. (Even by 1993 only 9% of the population was estimated to use a cell phone.) On this basis, relatively few Australians would have had 25 years of exposure to cell phones over the period examined by the study and this would have biased the study towards a “no effect” result.

    Was the Chapman study designed to reach the conclusion that cell phones don’t cause cancer?
    SNIP

    Read the full article here

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