Transcript Do Cell Phones Give You Brain Tumors? Do the Fields From Power Lines Give Children Leukemia? • 1 How do you go about.

Do Cell Phones Give You Brain Tumors? Do the
Fields From Power Lines Give Children
Leukemia?
• 1 How do you go about finding out?
• 2.Top down or bottom up.
• 3. Start with Epidemiology Studies or start
with the physics to chemistry to biology to
animal studies to health effects .
• 4. Basic problem the biological systems are
very complex, nonlinear, time dependent and
contain multiple feed back , feed forward and
repair processes.
Types Epidemiology Studies
• 1. Case Control Studies
• These are retrospective studies were you first
identify the cases and then select the controls
which match the cases as closely as possible
except for the variable being studied.
• 2. Cohort Studies
• Measure the parameters and confounders for the
whole population under study and follow them
for an extended period of time. The diseases are
Identified as the study progresses.
Common Weakness
• 1. In case control studies include
– A. Selection biases in the controls
– B. Exposure measurements
– C. Lack of an unexposed population
2. In cohort studies,
A. Very large study population required for rare diseases.
B. Example . Standard incidence rate for childhood cancers is
3.5/105 for females and 4.2/105 for males.
C. Exposure measurements Loss of parts of the population in
unequal numbers.
3.
Exposure misclassification, confounders, selection
bias. All are common problems.
More Problems and Conflicting Data
• 4. Other sources of the fields. Bias in the
populations selected, smoking, age, income
level, social norms.
• 5. Long delay times from initiation to
observation of many cancers.
• 1 You get conflicting studies?
• 2. You get irreproducible results.
• 3. Correlations may not be cause and effect.
Epidemiological Studies
ELF
• 1. Wertheimer, N. and Leeper, E., Electrical wiring
configurations and childhood cancer, Am.J.
Epidemiol., 1979, 109(3): 273–284.
• 2. Savitz, D., Wachtel, H., Barnes, F. et al., Case–
control study of childhood cancer and exposure
to 60-Hz magnetic fields, Am. J. Epidemiol., 1988,
128(1): 21–38.3.
• 3.Linet, M., Hatch, E., Kleinermann, R. et al.,
Residential exposure to magnetic fields and acute
lymphoblastic leukemia in children, N. Engl. J.
Med., 1997, 337(1): 1–7
Wertheimer, N. and Leeper, E., Electrical wiring
configurations and childhood cancer
• 1 This was the first study to show possible effects
of 60Hz magnetic fields on cancer.
• 2. A Case Control Study
• 3. It showed a weak association with power line
configuration.
• 4. Note they did not have the funding or the
ability to enter the house and make
measurements so the fields were inferred from
the power line configuration and proximity.
Some Basic Problems in Measuring the
Magnetic Fields.
• 1. They vary with time of day, time of year.
• 2. They vary with location.
• 3. The fields may be generated by other sources
than the power lines: plumbing, appliances .
• 4. People are not home all the time and may be
exposed to magnetic fields else where.
• 5. There was no model for the mechanism so that
you did not know what parameters to measure.
Approaches to Field Measurements
• 1. Limited access to the house to about 1hour so
what do you measure?
• 2. Need to spend time on questions with respect
to income, smoking, other possible confounders.
• 3. The fields vary by about 2 to 1 with time of day
and another 2 to 1 with season of the year.
• 4. Wiring Configuration Estimate from Size of
Wire, Distance to the house and from
transformer.
Measured Magnetic Fields in a House
• 1
Magnetic Fields and Current in the
Plumbing
Variations in the Magnetic Field with
Time of Day
• 1
Average Magnetic Field Measured in
Houses in 6 Studies
• 1
Additional Data from 12 Studies
• 1. For 2656 cases and 7084 controls OR of 1.68
and
CI of 95% at (1.23-2.31) for B>0.3µT
• 2.For 3023 Cases 10338 Controls OR=2, CI of 95% (1.273.13) for B>0.4µT compared with B<0.1µT
• 3. Lots of potential confounders,
– Selection Bias, Current in the Plumbing,
4. A big problem is the lack of a mechanism and an
understanding of how cancer is initiated and grows.
5. Correlation is not necessarily cause and effect.
6. Howard’s study. Correlation with traffic density also with
renting.
7.. Standard incidence rate 3.5/105 for females and 4.2/105 for
males.
ELF Epidemiological Studies
• 1 Summary Data is a slight positive correlation
between exposures for Baverage > 0.4 µT and a
possible causal association with ELF exposures
and childhood leukemia.
• 2. Adult Leukemia Results very weak
3.Electrical Appliances Results very weak
4. Occupational Studies show small cancer increases
for electrical workers. One New Zealand study
B>1µT OR= 3.2 CI (1.2-8.3) Pooled Analysis OR≈2
Exam
• Test 2 April 10th. Cover Chapters 6,8,9,10 of
book 1 Bioengineering and Biophysical
Aspects of Electromagnetic Fields
• And 6,7,8,9,10 of Biological and Medical
Aspects of Electromagnetic Fields
History for RF Concerns
• 1 Worries about Radar in the 1950s and 1960s
– A. High Powers short pulses.
2. Radio and TV Stations
A. Long term low levels
3. Only established mechanism is heating.
4. Long term low level effects if any are hard to
establish.
5. Miss classification, exposures?, long latency, low
incidences of disease
Current Issues
• 1. Cell phone transmitters,
– A. Typical power about 100W/channel
– B. Measured in Boulder Emax< 2V/m, P≈ 10mW/m2
or 1µW/cm2
• 2. Cell phones Radiation typically from
250mW to 600mW
• 3. WiFi
• 4. Some numbers for reference P=10W/m2,
E= 61.4V/m, B= 2.05x10-7T, H=0.163A/m
Typical SARs over 10 grams
Typical SARs over 1gram
Indoor Exposures
Far Field Exposures in Salzburg
RF Epidemiology Studies
• 1. Hardell L, Hallquist A, Mild KH, Carlberg M, Pahlson
A, and Lilja A. Cellular and cordless telephones and the
risk for brain tumors. Eur. J. Cancer Prev., 2002;
11(4):377–386.
• Hardell L, Nasman A, Pahlson A, Hallquist A, and
Hansson Mild K. Use of cellular telephones and the risk
for brain tumours: A case–control study. Int. J. Oncol .,
1999; 15(1):113–116.
• Inskip PD, Tarone RE, Hatch EE, Wilcosky TC, Shapiro
WR, Selker RG, Fine HA, Black PM, Loeffler JS, and Linet
MS. Cellular-telephone use and brain tumors. N. Engl.
J. Med ., 2001; 344(2):79–86.
Early Studies
• 1. Hardell, Showed increased incidence of
cancers on the side of the head where the
phone was held.
• 2. No overall increase in rate. 80% of the
Swedes had cell phones.
• 3. 7 studies show no effects.
• 4. 2 US studies show nothing. Problem short
term exposures and long latency for the
cancers.
Early Studies
• 1. I reviewed 20 studies and I found two I
thought deserved farther investigation.
• 2. Most of the exposure data was weak and it
was hard to separate the exposed from the
controls.
• 3. The two occupational studies I reviewed
were not convincing.
The Interphone Study
• An interview-based case–control study with 2708 glioma and 2409 meningioma
cases and matched controls was conducted in 13 countries using a common
protocol.
• Results A reduced odds ratio (OR) related to ever having been a regular mobile
phone user was seen for glioma [OR 0.81; 95% confidence interval (CI) 0.70–0.94]
and meningioma (OR 0.79; 95% CI 0.68–0.91), possibly reflecting participation bias
or other methodological limitations. No elevated OR was observed 5-10 years after
first phone use (glioma: OR 0.98; 95% CI 0.76–1.26;
• meningioma: OR 0.83; 95% CI 0.61–1.14). ORs were <1.0 for all deciles of lifetime
number of phone calls and nine deciles of cumulative call time.
• In the 10th decile of recalled cumulative call time, 51640 h, the OR was 1.40 (95%
CI 1.03–1.89) for glioma, and 1.15 (95% CI 0.81–1.62) for meningioma; but there
are implausible values of reported use in this group. ORs for glioma tended to be
greater in the temporal lobe than in other lobes of the brain, but the CIs around the
lobe-specific estimates were wide. ORs for glioma tended to be greater in subjects
who reported usual phone use on the same side
Cellular Phone Use and Risk of Benign and Malignant Parotid Gland
Tumors—A Nationwide Case-Control Study
Siegal Sadetzki1,2, Angela Chetrit1, Avital Jarus-Hakak1, Elisabeth Cardis3, Yonit
Deutch1, Shay Duvdevani4, Ahuva Zultan1, Ilya Novikov5, Laurence Freedman5, and
Michael Wolf2,4 , American Journal of Epidemiology, vol 167,no 4 ,2007
•
•
The objective of this nationwide study was to assess the association between
cellular phone use and development of parotid gland tumors (PGTs). The methods
were based on the international INTERPHONE study that aimed to evaluate
possible adverse effects of cellular phone use. The study included 402 benign and
58 malignant incident cases of PGTs diagnosed in Israel at age 18 years or more, in
2001–2003, and 1,266 population in- dividually matched controls. For the entire
group, no increased risk of PGTs was observed for ever having been a regular
cellular phone user (odds ratio ¼ 0.87; p ¼ 0.3) or for any other measure of
exposure investigated. However, analysis restricted to regular users or to
conditions that may yield higher levels of exposure (e.g., heavy use in rural areas)
showed consistently elevated risks. For ipsilateral use, the odds ratios in the
highest category of cumulative number of calls and call time without use of
hands-free devices were 1.58 (95% confidence interval: 1.11, 2.24) and 1.49 (95%
confidence interval: 1.05, 2.13), respectively. The risk for contralateral use was not
significantly different from 1. A positive dose-response trend was found for these
measurements. Based on the largest number of benign PGT patients reported to
date, our results suggest an association between cellular phone use and PGTs.
case-control studies; cellular phone; head and neck neoplasms; Israel; parotid
gland
Mechanisms
1.
2.
3.
4.
5.
Direct Electric Field Effects with High
Power Short Pulses. Membrane Damage
Heating, RF
Drift Currents and Dielectrophoresis
Change in Free Radical Lifetimes and
Chemical Reaction Rates
A Mechanism for Long Exposures at
Low Levels?
RF Standards
• 1. Some History back to the 50’s and radar, TV,
Radio
• 2. Results from injury at high levels and short
time exposures.
• 3. Different Philosophies Lead to different
numbers. U.S at the highest level not known
to be dangerous and a safety factor.
• 4. Heating at 60mW/cm2 shows damage
Standard set at 10mW/cm2 then up dated.
• 5. USSR Standard set at 10µW/cm2
RF Standards For Exposures
• 1. Types of Standards
– A. Voluntary
– B. Government Mandated
– .C. Different Philosophies and Enforcement
2. Emission Standards, Microwave Ovens, Cell
Phones Radio and TV stations, can be set for
multiple reasons.
3. Exposure Standards may be different for different
groups of people. Children, Workers, General
Public etc. Based on known damage?
Precautionary principle?
Multinational and National Standards Bodies
• 1, WHO, world health organization works to harmonize
standards
• 2. International Commission on Non Ionizing Radiation
Protection (ICNIRP) evaluates evidence and advises on
exposure limits. Non industrial members. These
recommendations are used by most of Europe and Asia
• 4. IEEE C95.1 RF, C95.6 ELF , ANSI, Open to all including
industry. Set other interoperability standards.
• 5. Local governments may impose lower limits.
California, Salzburg
Objective is to Protect Health
• 1. This comes down to questions of relative
risk. We do not live in a safe world!!
• 2. How much risk to you let people take on
themselves and when to your have
governments or industry set the standards.
• 3. Issue with electro sensitive people.
Standards Body Approach
•
•
•
•
•
•
1. Review of Literature
2. Check for good dosimetry.
3. Weight of evidence.
4. Establish Thresholds + Safety Factor
5. Evaluate and present for public review.
6. Current limit protect against short term
acute effects.
RF Exposure Reference Levels Electric Fields
RF Exposure Limits Magnetic Fields
Relative Risk of Getting Cancer
Risk
Source (Daily Exposure)
Carcinogen
0.3
Coffee (1 cup)
Hydrogen peroxide
0.4
Bread and grain products (average US diet)
Ethylene Dibromide
0.5
Food with pesticides (average US diet)
PCBs, DDE/DDT
8.0
Swimming in a pool (1 hour for a child)
Chloroform
9.0
Cooked bacon (100 grams)
Dimethylnitrosamine
30
Comfrey herbal tea (1 cup)
Symphytine
30
Peanut butter sandwich
Aflatoxin
60
Diet cola (12 oz.)
Sacchrin
70
Brown mustard (5 grams)
Allyl isothiosamine
90
Shrimp (100 grams)
Formaldehyde
100
Mushrooms (1 raw)
Hydrazines
300
Pain relief pill (300 mg)
Phenacetin
400
Bread (2 slices)
Formaldehyde
604
Breathing air at home (14 hours)
Formaldehyde
2,700
Regular cola (12 oz.)
Formaldehyde
2,800
Beer (12 oz.)
Ethyl alcohol
4,700
Wine (1 glass)
Ethyl alcohol
5,800
Breathing air at work (8 hours)
Formaldehyde
Cancer and Electric Power.
Cancer Increase
• 1
Cause
Days
Cause
Days
Being unmarried-male / female
3,500 / 1,600
Average job accident
74
Cigarette smoking-male / female
2,250 / 800
Drowning
41
Heart disease
2,100
Falls
39
Being overweight 30% / 20%
1,300 / 900
Fire-burns
27
Being a coal miner
1,100
Generation of electricity
24
Cancer
980
Suffocation
13
Low Socio-economic status
700
Fire arms accidents
11
Living in unfavorable state
500
Natural radiation / From nuclear industry
8 / 0.02
Army in Viet Nam
400
Medical x-rays
6
Smoking Cigar / Pipe
330 / 220
Poisonous gases
7
Job Dangerous / with RF exposure / safe
300 / 40 / 30
Coffee
6
Accidents Motor vehicle / to pedestrians
207 / 37
Oral contraceptives
5
Pneumonia, influenza / Diabetes
141 / 95
Reactor accidents-UCS / RCS
2 / 0.002
Alcohol (US average)
130
PAP exams
-4
Accidents in home
95
Smoke detector in home
-10
Suicide
95
Air bags in car
-50
Legal drug misuse
90
Mobile coronary care unit
-125
Risk From Power Sources
Membrane Damage
High Power Short Pulses