Wednesday, June 15, 2022

The UK Million Women Study of Cell Phone Use and Brain Tumor Risk

Journal of the National Cancer Institute publishes two letters critical of
UK Million Women Cell Phone/Brain Tumor Study


RE: Cellular Telephone Use and the Risk of Brain Tumors: Update of the UK Million Women Study

Moskowitz, Joel M. RE: Cellular Telephone Use and the Risk of Brain Tumors: Update of the UK Million Women Study. JNCI: Journal of the National Cancer Institute, 2022. doi: 10.1093/jnci/djac109.

No abstract

Excerpts

"Like the Danish Cohort study (1), the recent paper by Schüz et al. (2) which examined cellular telephone use and brain tumor risk in the Million Women Study suffered from poor exposure assessment which likely contributed to exposure misclassification. Moreover, participant attrition in this study was high (68%), and the study was underpowered as the analysis sample included few participants with heavier cell phone use, the group with the greatest brain tumor risk (2)."

"Although the Schüz et al. paper (2) provides sound advice to 'reduce unnecessary exposures,' the abstract in this paper is a disservice to public health because it ends with a misleading assertion: 'Our findings support the accumulating evidence that cellular telephone use under usual conditions does not increase brain tumor incidence.'  How can the authors of this paper argue that their results apply to 'usual conditions' when the amount of cell phone use in their analysis sample was much less than 'usual' for the United Kingdom (UK)?"

"... a recent meta-analysis of 46 case-control studies (6) found significantly increased brain tumor incidence with cumulative call time ≥ 1,000 hours (about 17 minutes per day over a 10-year period). Furthermore, Philips et al. (7) examined brain tumor incidence in England from 1995-2015 and found a two-fold increase in the standardized incidence of the most common malignant brain tumor, glioblastoma multiforme, along with reduced incidence of lower grade brain tumors which could indicate a tumor promotion effect from the increased uptake in cell phone use during this time period."

"In sum, the Schüz et al. study (2) provides no assurance of safety from brain tumors for most cell phone users, especially those who start using cell phones at a younger age than the middle-aged and elderly women who participated in this study."


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RE: Cellular Telephone Use and the Risk of Brain Tumors: Update of the UK Million Women Study

Birnbaum, Linda S, Taylor, Hugh S, Baldwin, Hillel, Ben-Ishai, Paul, Davis, Devra. RE: Cellular Telephone Use and the Risk of Brain Tumors: Update of the UK Million Women Study. JNCI: Journal of the National Cancer Institute, 2022. doi: 10.1093/jnci/djac110.

No abstract

Excerpts

"... a recent analysis of self-reported cell phone use of this original cohort by Shuz et al. 1 contains a number of serious errors and flaws of exposure measurement that undermine the validity of their widely publicized finding purporting that there is no risk of brain cancer from cell phone radiofrequency radiation (RFR) 1."

"Further, the National Toxicology Program (NTP) and Ramazzini Institute (RI)  experimental animal studies are inaccurately criticized as based on small numbers, inconsistency across species, and excessively high exposures 3,4."

"Current outdated regulatory limits for phone RFR rest on the incorrect long held assumption that non thermal levels are safe."

"The majority of animal and cell studies have found nonionizing RFR can induce oxidative stress- a key characteristic of human carcinogens and a way that RFR can initiate or promote tumor development as well as play a role in the development of other diseases 5.

Recent experimental and epidemiological studies indicate that RFR also induces cancers of the thyroid and breast 6,7. DNA damage and cancer in these state of the art studies signal the need for the public to reduce exposures to RFR now."


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Response to Moskowitz and Birnbaum, Taylor, Baldwin et al.

Schüz, Joachim, Pirie, Kirstin, Reeves, Gillian K, Floud, Sarah, Beral, Valerie. Response to Moskowitz and Birnbaum, Taylor, Baldwin et al. JNCI: Journal of the National Cancer Institute. 2022. doi: 10.1093/jnci/djac111.

No abstract

Excerpts

" We do agree, however, with both Moskowitz (1) and Birnbaum et al. (6) that our study does not include many heavy users of cellular phones."

"A large international prospective study of cellular telephone users including also men and younger women is underway [7] but results have not been published yet. Overall, our findings and those from other studies support our carefully worded conclusion that 'cellular telephone use under usual conditions [our emphasis] does not increase brain tumor incidence'. However, advising heavy users on how to reduce unnecessary exposures remains a good precautionary approach."


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March 30, 2022 (Updated April 1, 2022)

Cellular Telephone Use and the Risk of Brain Tumors: 
Update of the UK Million Women Study

Joachim Schüz, Kirstin Pirie, Gillian K Reeves, Sarah Floud, Valerie Beral, for the Million Women Study Collaborators. Cellular Telephone Use and the Risk of Brain Tumors: Update of the UK Million Women Study. JNCI: Journal of the National Cancer Institute, Volume 114, Issue 5, May 2022, Pages 704–711, doi: 10.1093/jnci/djac042.

Abstract

Background

The ongoing debate of whether use of cellular telephones increases the risk of developing a brain tumor was recently fueled by the launch of the fifth generation of wireless technologies. Here, we update follow-up of a large-scale prospective study on the association between cellular telephone use and brain tumors.

Methods

During 1996-2001, 1.3 million women born in 1935-1950 were recruited into the study. Questions on cellular telephone use were first asked in median year 2001 and again in median year 2011. All study participants were followed via record linkage to National Health Services databases on deaths and cancer registrations (including nonmalignant brain tumors).

Results

During 14 years follow-up of 776 156 women who completed the 2001 questionnaire, a total of 3268 incident brain tumors were registered. Adjusted relative risks for ever vs never cellular telephone use were 0.97 (95% confidence interval = 0.90 to 1.04) for all brain tumors, 0.89 (95% confidence interval = 0.80 to 0.99) for glioma, and not statistically significantly different to 1.0 for meningioma, pituitary tumors, and acoustic neuroma. Compared with never-users, no statistically significant associations were found, overall or by tumor subtype, for daily cellular telephone use or for having used cellular telephones for at least 10 years. Taking use in 2011 as baseline, there were no statistically significant associations with talking for at least 20 minutes per week or with at least 10 years use. For gliomas occurring in the temporal and parietal lobes, the parts of the brain most likely to be exposed to radiofrequency electromagnetic fields from cellular telephones, relative risks were slightly below 1.0.

Conclusion

Our findings support the accumulating evidence that cellular telephone use under usual conditions does not increase brain tumor incidence.

Open access paper: https://bit.ly/UKwomen2022

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Preliminary comments on "Cellular Telephone Use and the Risk of Brain Tumors: Update of the UK Million Women Study"

Like the earlier cell phone-brain tumor risk study that used data from the UK Million Women study (Benson et al., 2013), the current study (Schüz et al., 2022) is methodologically unsound due to limited assessment of cell phone use over time and misclassification of exposure. Furthermore, participant attrition from this prospective longitudinal study was very high which likely contributed to the fact that few participants in the main analysis were heavy lifetime cell phone users.

Thus, the study provides no assurance of safety to current cell phone users who use their phones more or start using at a younger age. The results of this study are also limited to the study population, namely middle-aged and elderly women who lived in the United Kingdom (UK).

Comparing their study to Interphone, a 13-nation case-control study which found that heavy lifetime use of cell phones (1,640 or more hours -- the top decile or 10%) was associated with significantly increased malignant brain tumor (i.e., glioma) incidence, the authors point out a major limitation of their new study:

"In INTERPHONE, a modest positive association was seen between glioma risk and the heaviest (top decile of) cellular telephone use (odds ratio = 1.40, 95% CI = 1.03 to 1.89). This specific group of cellular telephone users is estimated to represent not more than 3% of the women in our study, so that overall, the results of the 2 studies are not in contradiction (23)."

In the current study, only 18% of cell phone users talked on cell phones more than 30 minutes per week which corresponds to about 4 minutes per day or 26 hours per year which amounts to about 260 hours over a 10-year period -- far less use than what it would take to see a statistically significant association with brain tumor incidence. Even among daily cell phone users in this study, only 41% talked on their cell phones more than 30 minutes per week.

In contrast, we found in our meta-analysis of 46 case-control studies that "cellular phone use with cumulative call time more than 1000 hours statistically significantly increased the risk of tumors" which corresponds to at least 17 minutes per day over a 10-year period (Choi, Moskowitz et al., 2020).

The study also misclassified some "never" and "ever" users: Among participants who completed the 2001 and 2011 surveys, 45.8% of the 2001 never users talked on cellphones more than 1 minute per week (vs. 73.5% of ever users), and 8.8% talked on their cellphones more than 30 minutes per week (vs. 18.2% of ever users). 2001 never users talked on their cellphones an average of 4.3 years (vs. 8.9 years for ever users).

The current study did not control for cordless phone use, a potential confounder, which likely increases brain tumor risk. The study also failed to control for those who kept the cellphone away from their head during phone call phones by using the speaker phone or a headset.

The authors did not report any analyses to determine whether the selection of participants for this study or the high amount of participant attrition (68%) biased the study results.

The paper reported, "For the main malignant subtypes, glioma and glioblastoma, there was no indication of an increase, based on 937 and 702 cases, respectively, in cellular telephone users." 

How can the authors account for the results found in a study that examined brain tumor incidence from 1995 to 2015 in England (which includes about 84% of the UK population, the sampling frame for the current study)?  Philips et al., 2018 found a substantial increase in the incidence of the most common form of glioma, glioblastoma multiforme (GBM), over that time period along with a reduced incidence of lower grade tumors:

"We report a sustained and highly statistically significant ASR [age-standardized incidence rate] rise in glioblastoma multiforme (GBM) across all ages. The ASR for GBM more than doubled from 2.4 to 5.0, with annual case numbers rising from 983 to 2531. Overall, this rise is mostly hidden in the overall data by a reduced incidence of lower grade tumours."

This new paper concludes with the following advice: 

"Future research should target specifically the very heavy cellular telephone users, with attention to new features of a continuously evolving technology; hence, advising cellular telephone users on how to reduce unnecessary exposures remains a good precautionary approach."

Unfortunately, those who only read the abstract will see the following disingenuous conclusion:

"Our findings support the accumulating evidence that cellular telephone use under usual conditions does not increase brain tumor incidence."

The phrases, "accumulating evidence" and "under usual conditions" seem misleading given the limitations of the current study. Moreover, multiple case-control studies report increased brain tumor incidence with levels of cell phone use now considered quite common. The U.S. National Cancer Institute should be admonished for publishing this study in their hallmark journal, JNCI.

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No Link Between Cell Phones and Brain Tumors in Large UK Study