teenagers with mobile phones smoke less?
media showed interest in a report that a recent decline in teenage
smoking in the UK could be due to an increase in ownership of mobile
phones. In a letter to the British Medical Journal, Drs. Charlton
and Bates argue " that the mobile phone is an effective competitor
to cigarettes in the market for products that offer teenagers adult
style, individuality, sociability, rebellion, peer group bonding,
and adult aspiration."
were a number of email responses to the journal. Several correspondents
pointed out that a similar trend has not been seen in other countries
such as Italy, Australia, and Switzerland.
should be pointed out that in an ecological
study such as this a causal
relationship should not be assumed. There are probably many
other factors that play a part in the reported trends.
Charlton A, Bates C. Decline in teenage smoking with rise in mobile
phone ownership: hypothesis. BMJ 2000;321:1155.
cell phone users get more headaches than non-users?
letter in the same issue of the British Medical Journal reported
a study on cell phone users in Singapore. Headaches were thirty
per cent more likely in cell phone users than in those who did not
use a cell phone.
authors published an article on the same study in the November 2000
issue of Environmental Health Perspectives. They point out that
the use of cellular phones was not associated with a significant
increase of central nervous system symptoms other than headaches.
was a cross-sectional study,
which is a weak type of study to try to prove a causal
relationship, primarily because the temporal relationship of
the exposure and the outcome is obscured. Clearly, many factors
could affect the response seen in this paper, including personal
characteristics and predisposing medical conditions of the subjects.
References: Chia S-E, Chia H-P, Tan J-S, Vlassov
V. Health hazards of mobile phones. BMJ 2000;321:1155
Chia S-E, Chia H-P, Tan J-S. Prevalence of headaches among handheld
cellular telephone users in Singapore: A community study. Environmental
Health Perspectives 2000;108:1059-1062.
seminars examine safety of mobile phones
a recent issue of the Lancet, a British medical publication, two
papers discussed the safety of mobile phones. Dr G. Hyland reviewed
the physics and biology of mobile telephony. He argues that low
intensity, pulsed radiation used in mobile phones and their base
stations can exert subtle, non-thermal influences on living organisms.
He argues that these may arise because of a synergy between the
frequencies generated by the phone and electrical activities of
the organism. Hyland further suggests that living organisms may
react not only to the frequency of the microwave carrier but also
to the lower frequency pulsings, at 2 Hz and 8.34 Hz, which are
features of some systems such as the TDMA system.
the second paper Dr K. Rothman discusses epidemiological
evidence on health risks. He states that there is no clear evidence
of an association
with brain tumours or other malignancies but points out that there
have been few studies of the effects of radiofrequency exposure.
At present, he says, "the main public-health concern is clearly
motor vehicle collisions, a behavioural effect rather than an effect
of radiofrequency exposures as such."
points out in an accompanying commentary that there are problems
with the evidence that Hyland cites in his paper. These include
the lack of reproducibility, and the absence of either a direct
quantitative link between cause and effect or a proven causative
Dendy PP. Mobile phones and the illusory pursuit of safety. Lancet
Hyland GJ. Physics and biology of mobile telephony. Lancet 2000;356:1833-1836.
Rothman KJ. Epidemiological evidence on health risks of cellular
telephones. Lancet 2000;356:1837-1840.
research on cell phones and cancer
in the paper discussed above, also discusses ongoing research that
is studying the relationship between cell phones and cancer. One
study, coordinated by the National Cancer Institute in the US, is
expected to report its findings next year. PD Inskip and colleagues
reported the design of this study in an article in Radiation Protection
Dosimetry last year.
recent article in Epidemiology reviews the discussion that took
place at an International Workshop last year on the relation between
mobile telephones and tumours of the brain, head, and neck. Various
current research studies are mentioned. For further information
on this see "What's New Archives, April 2000 and November 1999.
Inskip PD, Hatch EE, Stewart PA, et al. Study design for a case-control
investigation of cellular telephones and other risk factors for
brain tumours in adults. Radiation Protection Dosimetry 1999;86:45-52.
M, Michaelis J, Wahrendorf J. Workshop on research into the health
effects of cellular telephones. Epidemiology 2000;11:609-611.