Radon in the air of ordinary homes can cause lung cancer, particularly in smokers Chair: Prof' Alex

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Radon in the air of ordinary homes can cause lung
cancer, particularly in smokersChair Prof.
Alex MarkhamChief Executive, Cancer Research
UKSpeakers .
1. Sarah DarbyProfessor of Medical
Statistics,University of Oxford2. Sir Richard
PetoProfessor of Medical Statistics and
Epidemiology,University of OxfordFunding
Cancer Research UK European Commission
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Radon in the air of ordinary homes can cause
lung cancer, particularly in smokers

• Radon Colourless, odourless, radioactive gas.
• Natural from radioactive disintegration of the
  uranium atoms in ordinary rocks and soil.
• Radon half-life only 4 days from when it forms,
  so most radon disintegrates safely while still
  underground.

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Radon in the air of ordinary homes can cause
lung cancer, particularly in smokers

• Some radon diffuses through the soil and escapes
  into the atmosphere or into houses.
• Radon in homes accounts for about half of all
  non-medical exposure to ionising radiation in the
  UK.
• When inhaled, radon can cause lung cancer,
  especially in people whose lungs are already
  damaged by tobacco.

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Radon in the air of ordinary homes can cause
lung cancer, particularly in smokers

• Radon exposure used to be very high in some
  underground mines radon hazards first
  recognised in some mineral miners.
• Uncertain how to extrapolate from findings in
  heavily radon-exposed miners to the much lower
  risks in ordinary homes.

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Radon in the air of ordinary homes can cause
lung cancer, particularly in smokers

• 13 European studies have tried to measure risks
  from radon in homes.
• All too small to be reliable on their own, but
  together they add up to the largest study ever
  done and demonstrate definite hazards,
  particularly for smokers.
• The extra risk is, approximately, proportional to
  the usual amount of radon in the home.

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Radon in the air of ordinary homes can cause
lung cancer, particularly in smokers

• Radon in homes causes about 20,000 lung cancer
  deaths a year in Europe
• (9 of all lung cancer deaths, and 2 of all
  cancer deaths).
• Radon causes 1000 lung cancer deaths a year in
  the UK (1 of all cancer deaths).

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Radon in the air of ordinary homes can cause
lung cancer, particularly in smokers

• Bq/m3 (becquerels per cubic metre)
• radon disintegrations per second per
  . cubic metre of air.
• 600 Bq/m3 doubles the lung cancer risk.
• 200 Bq/m3 adds 1/3 to lung cancer risk.

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Radon in the air of ordinary homes can cause
lung cancer, particularly in smokers

• But, just controlling exposures above an action
  level of 200 Bq/m3 avoids only 10 of radon
  hazards.
• 1000 (50/year) to reduce high radon levels in
  existing buildings.
• 100 extra (during building) to make
  damp-proofing membranes in new houses radon-proof.

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Dangers of radon greatest for smokers

• On average in Europe, risks of getting lung
  cancer before age 75 at usual radon levels of
  0,100, 400 Bq/m3 (radon disintegrations per
  second per cubic meter of air) are
• Non-smokers 0.4, 0.5, 0.7
• Smokers 10, 12, 16
• (25x greater than in nonsmokers).

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Cumulative absolute risk of death from lung
cancer by age 75 years versus usual radon
concentration at home
Darby et al. BMJ 21 Dec 2004
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Age Doll et al. BMJ
20043281519-1528
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• Possible strategies
• Stop smoking most people killed by
  radon-induced lung cancer would never have
  developed the disease if they hadnt also
  smoked.
• Protect existing houses that have a lot of radon
  (about 1000 each, plus 50/year).
• Building regulations when installing a
  damp-proof membrane under a new house, make it
  radon-proof as well (about 100 extra).