Is Your Cell Phone Killing You? - PowerPoint PPT Presentation

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Is Your Cell Phone Killing You?

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  1. Is Your Cell Phone Killing You? Mobile Communications Fair Sponsored by Tech-Connect Presented by Tim Weber, PRA International February 23, 2010

  2. Outline • Background/Introduction • Definitions • Commonly studied health risks • What does science tell us? • Do cell phones really cause cancer? • What are the important conclusions? • Concerns about kids & phones • What is the future of the research? • Q&A

  3. Speaker’s Background • Tim Weber, PhD • Bachelor’s in Chemical Engineering, Bucknell University • Doctorate in Chemical Engineering, University of Virginia • Doctoral research on lovastatin, active ingredient of Mevacor®; led to US patent • 12+ years with PRA International, a contract research organization • Contributed to the approval of at least 5 drug products currently marketed in the US

  4. Introduction/History • 1st generation (1G) • Analog phones; early 80’s; 450 & 900 MHz • 2nd generation (2G) • Digital (Global System for Mobile Communication, or GSM); early 90’s; 900 & 1800 Mhz • 3rd generation (3G) • Universal Mobile Telecommunication System (UMTS); ca. 2003; 1900-2200 MHz • 4th generation (4G) • Still relatively new; frequency 2000-8000 MHz

  5. Introduction/History, cont’d. • Each successive generation has operated at a higher frequency: more apps = more power • Usage increasing…and fast! • 5% in 1998  67% (4.6 billion) in 20091 • Almost half of US children aged 8-12 are cell phone users 1 International Telecommunications Union. The World in 2009: ICT Facts and Figures. http://www.itu.int/ITU-D/ict/material/Telecom09_flyer.pdf

  6. Some Basic Definitions • CTIA – International Association for the Wireless Telecommunications Industry (www.ctia.org) • RF-EMR (RF) – Radio frequency electromagnetic radiation • SAR – Specific absorption rate; how much RF is absorbed into the body when exposed to a radiation source, such as a mobile device (measured in W/kg; ≤1.6 in US; ≤2.0 in EU) • Meta-analysis – analyzes multiple studies with similar research objectives

  7. Definitions (2) - Odds Ratio • 50/100 men and 25/100 women are color blind • p1 = probability of a man being color blind • p2 = probability of a woman being color blind • Odds Ratio: (p1/(1-p1))/(p2/(1-p2)) • In our example: • (0.5/(1-0.5))/(0.25/(1-0.25)) • (0.5/0.5)/(0.25/0.75) • (1/(1/3)) = 3 • Conclusion: A man is 3 times more likely than a woman to be color blind

  8. Definitions (3) Relative Risk • Same groups of men & women • Relative Risk: p1/p2 • In our example: • 0.5/0.25 = 2 • Conclusion: The risk of a man being color blind is twice that of a woman

  9. Case-Control Studies • Used widely in epidemiological studies • Compare individuals who have a certain condition (cases) with those who do not (controls) • Controls should be matched for age, gender, and ethnicity • Can suggest, but cannot prove, causality of a particular condition (e.g., tobacco consumption and lung cancer)

  10. Case-Control Studies, cont’d. • To date, most widely used tool for studying health risks of cell phone usage • Cell phone usage has mushroomed in just the last decade or so • Relies on memory and anecdotal evidence of past usage • Typically in-person or telephone interviews

  11. Commonly Studied Health Risks • Possible association with cancer • Source of distraction while driving • Poor fertility/DNA damage in males • Miscarriage/morbidity in unborn children • CNS (migraine, vertigo, ALS, MS, epilepsy) • Interference with pacemakers, hearing aids, and defibrillators • Exposure to radiation from cell phone towers

  12. What Does Science Tell Us? • RF-EMR is similar in energy to AM/FM radio waves, microwaves, and infrared heat lamps • non-ionizing radiation • not capable of breaking molecular bonds (e.g., DNA) • does not enter body tissues • same type of radiation used in MRI technology

  13. Do Cell Phones Cause Cancer? • Searching on “cell phones cancer” returns almost 24 million Google hits and 300 PubMed articles • The American Cancer Society, FDA, National Cancer Institute, FCC, CDC, and National Toxicology Program (NTP) have all issued statements saying that there is, at present, no definite link, but that more research is needed • The EPA, NTP, and International Agency for Research on Cancer (IARC) have not classified cell phones as to their carcinogenicity

  14. What Types of Tumors? • Astrocytoma – brain cancer (star-shaped tumor) • Acoustic neuroma – benign tumor that affects the 8th cranial nerve (runs from brain to inner ear) • Glioma – brain cancer that forms in the glial cells (surround and support nerve cells) • Meningioma – slow-growing tumor that forms in the meninges (tissue surrounding brain and spinal cord) • Testicular cancer • Non-Hodgkin’s lymphoma • Salivary gland tumors • Pituitary tumors

  15. What Does the Literature Tell Us? • Could do a daylong Mobile Fair just on this topic • Slides that follow are meant to be representative, not exhaustive • Other sources of info: • American Cancer Society (www.cancer.org) • National Cancer Institute (www.cancer.gov) • CNET (www.cnet.com) • WebMD (www.webmd.com) • Environmental Working Group (SAR values; http://www.ewg.org/cellphone-radiation/)

  16. Kristiansen, et al., Bioelectromagnetics (2009) • Results from 2006 Danish phone survey (N=1004) • 28% worried about exposure to mobile phone radiation (82% worried about pollution) • 49% say mortality risk on par with dying from a lightning strike; 7% on par with dying from smoking-induced lung cancer • Overall conclusion: most aren’t terribly concerned, but a minority is very concerned

  17. Hardell & Carlberg, International Journal of Oncology (2009) • Case-control study 1997-2003 • 2159 cases with brain tumors; 2162 population-based controls • Ipsilateral astrocytoma and acoustic neuroma after >10 years of use: OR = 3.3 and 3.0, respectively • Highest risk among users whose first use was before age 20

  18. Ahlbom, et al., Epidemiology (2009) • Meta-analysis of 16 studies published 1999-2008 • Methodological deficiencies of case-control studies: selective nonresponse and exposure misclassification • No increased risk of fast-growing tumors with ~10 years of cell phone use; more time needed to decide on slow-growing • Maximum risk vs. detectable risk: should be a detectable signal by now if there really is an increased risk

  19. Rothman, Epidemiology (2009) • Tumors of interest are all rare types • Insufficient exposure of users (long induction times for tumors) • Effects, if any, resulting in today’s tumors likely from 1G and 2G phones • Accurate exposure assessment difficult if not impossible • Case-control studies are subject to recall bias

  20. What Does the Literature Tell Us? • Majority of authors find no definitive link • Why does it seem to be Hardell vs. everyone else? • Shortcomings of current study designs & research • Some increases in overall brain cancer rates: better tests; earlier diagnoses; MRI/CT scans • Most evidence supporting a link to cancer comes from EU-based studies where the maximum SAR is higher than the US • INTERPHONE vs. International EMF Collaborative; not sure either of these has much merit

  21. Concerns about Kids & Phones • Seem to be sound scientific reasons to monitor usage of cell phones by kids: • Nervous systems are still developing • Brain tissue is more conductive than adults • More RF penetration due to smaller head size • Longer lifetime of exposure (first use typically well before 10)

  22. Concerns about Kids (2) Estimation of the absorption of electromagnetic radiation from a cell phone based on age (frequency GSM 900 Mhz) (on the right, a scale showing the specific absorption rate at different depths, in W/kg) (Gandhi et al. IEEE Trans Microwave Theor Tech. 1996;44:1884-1897. ©1996 IEEE). Figure from Han, et al., in Surgical Neurology 72 (2009) 216-222

  23. What Is the Future of Research? • Better methods to measure and quantify RF exposure (e.g., is a 10-minute call the same as 10, 1-minute calls?) • Better models to estimate SAR away from the surface • Identifying the cellular target of RF-EMR • Well-designed prospective cohort studies to evaluate cancer, CNS, reproduction, interference, etc.

  24. Future Research (2) • Longer-term (15-20 years) case-control studies • most tumors take at least 10 years to develop • More research involving children • By constantly developing higher-frequency devices and using them more often, are we escalating the risk faster than our bodies can adjust? • Is texting the answer? • Topics that haven’t even arisen yet (second-hand radiation, anyone?)

  25. Questions? If you have questions, please don’t hesitate to contact me: Tim Weber WeberTim@PRAINTL.com 434-951-3212 (W) 434-882-1940 (M)