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Archive for 29 oktober, 2013

Sir Austin Bradford Hill gav i ett berömt tal år 1965 synpunkter på sambandet mellan tobaksrökning och lungcancer. Epidemiologiska studier kan visa en ökad risk på en association men inte att exponeringen i fråga orsakar den åkomma som undersöks, t.ex. cancer.

Bradford Hill presenterade 9 synpunkter, ofta kallade för kriterier, för ett orsakssamband. Han påpekade dock att inte alla villkor behöver vara uppfyllda för att en exponering skall anses orsaka en sjukdom.

Vi har använt oss av dessa villkor för att bedöma om exponering för radiofrekventa fält (mikrovågor) från mobiltelefoner och trådlösa bordstelefoner (DECT) kan orsaka hjärntumörer. Vi finner därvid att de flesta kriterier är uppfyllda och att radiofrekventa fält skall anses orsaka vissa former av hjärntumörer (elakartade och acusticusneurinom). Detta motsvarar Grupp 1 enligt IARC vid WHO ”Sufficient evidence in humans”.

Vår artikel har publicerats efter sedvanlig granskning i den vetenskapliga tidningen Reviews on Environmental Health (DOI 10.1515/reveh-2013-0006). Nedan ges en engelsk sammanfattning av artikeln.

Lennart Hardell and Michael Carlberg

Using the Hill viewpoints from 1965 for evaluating

strengths of evidence of the risk for brain tumors

associated with use of mobile and cordless

phones

Abstract

Background: Wireless phones, i.e., mobile phones and

cordless phones, emit radiofrequency electromagnetic

fields (RF-EMF) when used. An increased risk of brain

tumors is a major concern. The International Agency for

Research on Cancer (IARC) at the World Health Organization

(WHO) evaluated the carcinogenic effect to humans

from RF-EMF in May 2011. It was concluded that RF-EMF

is a group 2B, i.e., a “possible”, human carcinogen. Bradford

Hill gave a presidential address at the British Royal

Society of Medicine in 1965 on the association or causation

that provides a helpful framework for evaluation of

the brain tumor risk from RF-EMF.

Methods: All nine issues on causation according to Hill

were evaluated. Regarding wireless phones, only studies

with long-term use were included. In addition, laboratory

studies and data on the incidence of brain tumors were

considered.

Results: The criteria on strength, consistency, specificity,

temporality, and biologic gradient for evidence of

increased risk for glioma and acoustic neuroma were

fulfilled. Additional evidence came from plausibility and

analogy based on laboratory studies. Regarding coherence,

several studies show increasing incidence of brain

tumors, especially in the most exposed area. Support for

the experiment came from antioxidants that can alleviate

the generation of reactive oxygen species involved in

biologic effects, although a direct mechanism for brain

tumor carcinogenesis has not been shown. In addition,

the finding of no increased risk for brain tumors in subjects

using the mobile phone only in a car with an external

antenna is supportive evidence. Hill did not consider all

the needed nine viewpoints to be essential requirements.

Conclusion: Based on the Hill criteria, glioma and acoustic

neuroma should be considered to be caused by RF-EMF

emissions from wireless phones and regarded as carcinogenic

to humans, classifying it as group 1 according to the

IARC classification. Current guidelines for exposure need

to be urgently revised.

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