Chernobyl Forum EGH3 NonCancer Diseases - PowerPoint PPT Presentation

Title: Chernobyl Forum EGH3 NonCancer Diseases


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Chernobyl ForumEGH-3 Non-Cancer Diseases

• September 6,7, 2005
• Vienna International Center

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EGH-3 Committee

• M. Balonov, IAEA
• V. Bebeshko, Ukraine
• E. Bromet, USA
• Z. Carr, WHO
• F. Darroudi, Netherlands
• J. Havenaar, Netherlands
• J. Hendry, IAEA
• E. Kapitonova, Belarus
• N. Korol, Ukraine

• V. Ivanov, Russia
• F. Mettler, USA
• K. Neriishi, Japan
• Y. Shibata, Japan
• G. Souchkevtich, Russia
• S. Yamashita, WHO
• B. Worgul, USA

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1991
1996
1996
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UNSCEAR 2000/2006
2000
2006
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Issues with non-cancer effects

• Data is often descriptive/ subjective
• Inconsistent diagnostic criteria
• Data often presented without context
• Data often presented without control groups
• Data without dose estimate or dose response
• Data often for only one country
• Conclusions are less scientifically rigorous than
  the cancer data
• Could not cover every claimed health effect

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Various mechanisms for non-cancer health effects
Mental Health Psychological
Cancer
Radiation burns, cataracts
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2003
2004
Ukraine
Russia
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8 Major issues addressed by EGH-3

• Cataracts
• Cardiovascular diseases
• Cytogenetic markers and significance
• Immunological system effects
• Heritable effects, birth defects, childrens
  health
• Mental,psychological and nervous system effects
• Mortality due to the accident
• Medical programs and medical monitoring

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Cataracts

• Issues
• - Cataracts do occur at high doses
• - Trained observers. Coherent criteria
• Consensus
• Changes do occur at doses lower than in prior
  literature
• Gaps
• Is there a threshold ?
• Actual doses to the lens (esp. beta)
• Ultimate effect on visual function
• Effect on ocular tissue other than the lens

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Lens
Front
Back
Vano Worgul
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Identifiable changes ? significance
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Cataracts

• Conclusion
• Cataracts may occur at doses of 0.25 Gy
• Recommendations
• Continued follow-up of liquidators and radiation
  workers
• Careful evaluation of doses to lens
• Continue study of those already recruited
• Ocular examination of general population probably
  unwarranted and wasteful

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Cardiovascular diseases

• Issues
• High doses can cause cardiovascular disease
• Complicated by smoking (more deaths than due to
  lung cancer), genetics and diet.
• Possible relation in atomic bomb survivors
• Consensus
• Only data from Russian liquidators
• Increase is not correlated with MI and ischemic
  heart disease
• Gaps
• Dose estimates vs cardiovascular disease
• Lack of good control groups and small cohorts

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Chernobyl ARS survivor and physicians
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Cardiovascular diseases

• Conclusion
• ARS survivors are likely at increased risk
• Russian liquidators show increased risk but this
  needs to be validated and further evaluated
• Radiation effect not fully substantiated but
  small effect cannot be excluded
• Recommendations
• Validation studies of liquidators in other
  countries with control groups dosimetry, common
  diagnostic criteria and standardized protocols
• Animal studies to investigate mechanisms

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Cytogenetic markers

• Issues
• There are different markers in lymphocytes of the
  peripheral blood which persist for different
  times
• Useful for biodosimetry (avarage bone marow dose)
• Is there clinical significance ??
• Micro and mini satellite data inconsistent
• Consensus
• FISH can detects doses as low as 0.25 Gy
• None appear to result in direct damage that
  increases cancer or other health effects
• Gaps
• More studies to correlate markers with dose
• Studies to directly correlate with markers and
  health in the same individuals

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Chromosome analysis
Dicentric (stable)
Fragment (unstable)
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FISH (fluorescent in-situ hybridization)Individua
l chromosome painting
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Cytogenetic markers

• Conclusion
• No direct relationship shown with health or
  disease
• Used for dose estimation and as a rough estimate
  of potential future risk from cancer
• Recommendations
• Correlation of biological dosimetry with
  epidemiology

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Immunological effects

• Issues
• Very high doses of radiation can reduce immune
  function
• Low doses of radiation may have laboratory
  findings but .? effect on discernable illness
• Various studies are not coherent with regard to
  type and timing of findings
• Consensus
• Reported changes are in peripheral lymphocytes
  and remain detectable. The cause is not clear
  (diet, chemicals, chronic infections or radiation
• Gaps
• Role of confounding factors,

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Immunological effects

• Conclusions
• There is significant variation in reported
  results and many are in conflict with the atomic
  bomb survivor literature
• At doses of less than several tens of mSv, no
  clinical effects have been related to lymphocyte
  immune changes
• Recommendations
• -studies should continue after in persons with
  high absorbed doses.
• -studies at doses at less than several 10s of
  mSv are unlikely to be of value
• - studies on children with individual absorbed
  doses and control groups may be of value

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Heritable, reproductive effects, childrens
health

• Issues
• Hereditary changes in human offspring not shown
  in the literature
• Fertility. Permanent changes not likely at doses
  to the general population or many liquidators
  (below 0.2 Gy). Birth rate issues clouded by high
  medical abortion rate..
• In-utero direct effects, malformations (not
  likely below 0.1-0.2 Gy).
• Infant mortality rates
• Consensus
• No definite radiation effects. Infant mortality
• high in the general population

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Congenital malformations (9 defined types) in
Belarus
Low contamination
Lazjuk
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Downs syndrome in Belarus
Zatsepin
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Infant mortality (Ukraine)
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Infant mortality in contaminated oblasts and
Ukraine as a whole
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Infant mortality (Ukraine)
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Heritable, reproductive effects, childrens
health

• Gaps
• Fundamental cause of high infant mortality
• Conclusions
• No clear radiation effects on fertility,
  malformations or infant mortality
• No conclusion on adverse complications of
  pregnancy stillbirths etc
• Reported decrease in health of children not
  related to radiation dose. Several possible
  causes
• Hereditary effects not seen and very unlikely

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Heritable, reproductive effects, childrens
health

• Recommendations
• Investigate basic causes of high infant mortality
  in clean and contaminated areas
• As a public health measure, continue registers on
  reproductive health outcomes
• Actions to reduce psychosocial measures for those
  exposed a s children
• Discourage studies that do not provide baseline
  values, time period, estimates of absorbed dose,
  blinded evaluation and analysis etc.

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Psychological, mental and nervous system effects

• Issues
• - ? In-utero mental retardation
• ? Direct effects on the brain among highly
  exposed
• Psychological consequences
• Consensus
• Psychological effects are the largest public
  health impact from the accident
• May not be possible to disentangle accident
  effects from other stressors
• High levels of anxiety and unexplained medical
  complaints continue up to the present

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Psychological, mental and nervous system effects

• Gaps
• Few studies integrate mental and physical health
• Systematic research on highly exposed workers
• Adequate studies of children and adolescents
• Best intervention to reduce level of anxiety
• Conclusions
• Serious mental health impact mainly at a
  sub-clinical level with implications for
  subjective health, reproductive health, medical
  service utilization
• Need for timely and accurate information
  communication in disasters

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Psychological, mental and nervous system effects

• Recommendations
• -Generate general public health policy due to
  high rates of psychiatric and substance disorders
  in population not limited to Chernobyl exposed
• - Additional research on most highly exposed
  (ARS) for cognitive changes with imaging or
  pathological correlation
• Accounting for psychological effect when
  conducting epidemiological studies of other
  health effects
• Major increase mental health training for primary
  physicians and nurses
• Move locus of care to primary care settings

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Mortality due to the accident

• Issues
• Short term deaths (very well known)
• Intermediate deaths (reasonably well known)
• Long term (estimates)
• Issues with major changes in lifespan due to
  unrelated causes
• Data on liquidators (Russia), public (Ukraine)
• Consensus
• No detectable increase in general population,
  small increase in liquidators (but lower than in
  general population.

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Major changes in lifespan over last 2 decades
even in non-contaminated areas complicate analysis
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Chernobyl fireman
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SMR all causes Russian liquidators vs. general
population (1991-98
Ivanov
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SMR Non-cancer diseases Russian liquidators vs.
general population (1991-98)
Ivanov
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Mortality of general population
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Contaminated areas of Ukraine
16 vs 18.5 ? Age distribution difference
Korol
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Mortality due to the accident

• Conclusions
• Acute 28 persons due to ARS 1986,
  2 in explosion
• 134 ARS 1987-2004
  various reasons
• Intermediate 216 excess (4.6 ,1991-1998)
  among Russian
• workers but lower
  mortality than among general
• population
• - Long term 4,000 due to radiogenic
  cancer and leukemia
• in 600,000 persons.
  Difficult to detect. More people at
  doses lt50 mSv, uncertain effect
• Recommendations
• - Continue liquidator mortality studies.
• - Mortality studies of general population
  mortality are unlikely to
• be useful relative to the accident due to
  low signal to noise ratio
• and confounding. Useful general public
  health tool.

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Medical programs and medical monitoring

• Issues
• Monitoring in place for liquidators, asymptomatic
  children and general public of contaminated
  territories
• What is the beneficial effect vs. the cost/need
• Consensus
• Initial medial triage and ARS treatment saved
  many lives
• Screening for many cancers or leukemia is not
  effective
• Long term follow-up of asymptomatic persons who
  received low doses is not likely to provide any
  medical benefit
• Need for monitoring of highly exposed and medical
  care for symptomatic individuals continues

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Medical follow-up after high exposures
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Medical programs and medical monitoring

• Gaps
• Which interventions were effective in highly
  exposed individuals
• Effect of screening for thyroid cancer on
  outcomes
• Conclusions
• Continue medical monitoring of asymptomatic
  individuals may have a negative impact
• Recommendations
• Reevaluate cost/benefit of monitoring large
• asymptomatic populations
• Limited research on selected populations
• Continue thyroid screening but evaluate
• Continue on sensitive/high risk persons

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Cancer screening

• Cancer is the major direct health below 1 Gy
• Some cancers are poorly or not radiogenic (e.g.
  prostate, uterine cervix, lymphoma)
• Some do not have proven effective screening tests
  (e.g. leukemia, pancreas, lung)
• Radiation levels to double risk of most solid
  cancers is above 1 Gy
• If there is an effective cancer screening test,
  it should be used on the general public
  regardless of radiation exposure.

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Risks of death in an exposed population (0.25 Sv)
Radiation excess deaths
Expected non-radiation cancer deaths
Non cancer deaths
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Major conclusions

• Cataracts possible lower doses-more research
• Cardiovascular possible effect, more research
• Cytogenetic markers. For dose/risk estimate. No
  direct health effect
• Immunological. Confused conflicting laboratory
  data. No definite clinical effect. Research high
  dose liquidators.
• Congenital malformations/ Infant mortality /
  childrens health. No definite increase due to
  radiation. General infant mortality high (general
  public health concern). Issues about
  psychological aspect of those exposed as children
  and adolescents

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Major conclusions (contd)

• Mortality- possibly thousands over time due to
  accident but hard to detect on current mortality
  background and changes. High in general
  population with significantly reduced lifespan
  over last decade
• Psychological. Major issue continues. Need to get
  away from invalid concept. Look at interventions.
  Multiple stressors. Need overall look at overall
  mental health programs in light of substance
  abuse, suicide etc.
• Medical follow-up/ screening. Medical follow-up
  of highly exposed should be continued. Screening
  for exposed populations should be reconsidered
  and may be better used for other general public
  health areas of concern.

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A Joint Project of 8 UN Agencies
Additional material and detail in the actual
report. Please read it
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