Kiev SIBecker

HEALTH EFFECTS PROJECTS: 

HEALTH EFFECTS PROJECTS French-German Initiative Chernobyl

LEUKAEMIA INCIDENCEIN BELARUS, RUSSIA, UKRAINE: 

A prospective cohort study with control group Analysis of joint data 1980 - 1997 Dr SI Becker MPH postgrad LEUKAEMIA INCIDENCE IN BELARUS, RUSSIA, UKRAINE

Slide3: 

Study centres in Belarus, Russia, Ukraine: Research Institute for Haematology and Blood Transfusion Minsk, Belarus. Project leader: Dr. VN Gapanovich Medical Radiological Research Centre of the RAMS Obninsk, Russia. Project leader: Prof. VK Ivanov Ukrainian Research Centre for Radiation Medicine Kiev, Ukraine. Project leader: Prof. AYe Prisyazhniuk Dr SI Becker MPH postgrad

Slide4: 

Q: What is the difference between a statistician and a physician?

Slide5: 

Q: What is the difference between a statistician and a physician? A: A physician makes an analysis of a complex illness, a statistician makes you ill with a complex analysis

Slide6: 

Why the special interest in leukaemia? Risik of leukaemia through ionizing radiation is well established on the grounds of the data from Hiroshima and Nagasaki ERR/Sv of leukaemia is higher than that of solid tumours - of leukaemia: ERR/Sv 4.2-5.2 - of solid tumours: ERR/Sv 0.63 Short latency period (2-5 years) The risk of leukaemia is determined mainly by the contamination with caesium 137

Slide7: 

Leukaemia is an important focus of fear in the general population

Slide8: 

Ground contamination with 137 caesium

Slide9: 

Affected population today 6.7 million people live in regions with 137caesium contamination above 37.000 Bq/m² 1.4 million people live in regions with 137caesium contamination above 185.000 Bq/m² 1/5 -1/6 are children under the age of 15

Slide10: 

Is there an increase of leukaemia incidence in the general population in the contaminated areas as a result of the ChNPP Accident?

Slide11: 

Study design: prospective cohort study with control group comparison of leukaemia incidence rates - in contaminated and control regions - before and after the accident (taking into account the latency)

Slide12: 

Material all leukaemia cases (1980-1997) in the study regions - taken from population-based registries that had been established and operating for many years before the ChNPP Accident - data base completed by active registration of formerly non- registered cases - careful verification of all cases exclusion of non-cases - validation of the project data base population data

Slide13: 

Ground contamination with 137 caesium

Population (in 1 000): 

Population (in 1 000)

Slide15: 

Completeness, quality, and characteristics of the data

Slide16: 

Population- based cancer registries Health Care System

Slide17: 

Active registration - completeness of registered cases leukaemia in the Ukraine

Slide18: 

Verification of the data – leukaemia in Russia

Slide19: 

Verification of data - leukaemia in Russia

Validation of data - distribution of cases by period: 

Validation of data - distribution of cases by period

Validation of data - distribution of cases by age: 

Validation of data - distribution of cases by age

Different forms of leukaemiain the different rayons under study in 1980-1997: 

Different forms of leukaemia in the different rayons under study in 1980-1997

Different forms of leukaemia in adultsin the three time periods: 

Different forms of leukaemia in adults in the three time periods

Different forms of leukaemia in childrenin the three time periods: 

Different forms of leukaemia in children in the three time periods

Slide25: 

Analysis

Age-specific incidence rates with 95% CI‘s (Poisson): 

Age-specific incidence rates with 95% CI‘s (Poisson)

Age-specific incidence rates with 95% CI‘s (Poisson): 

Age-specific incidence rates with 95% CI‘s (Poisson)

Age-specific incidence rates with 95% CI‘s (Poisson): 

Age-specific incidence rates with 95% CI‘s (Poisson)

Crude and age-standardised incidence rates: 

Crude and age-standardised incidence rates

Age and sex structure of the study population: 

Age and sex structure of the study population

Crude and age-standardised (world) incidence rates; contaminated regions: 

Crude and age-standardised (world) incidence rates; contaminated regions 95% CI‘s (Poisson) for the crude rates regression line for the standardised rates

Crude and age-standardised (world) incidence rates; control regions: 

Crude and age-standardised (world) incidence rates; control regions 95% CI‘s (Poisson) for the crude rates regression line for the standardised rates

Age-standardised (world) incidence rates;direct comparison : 

Age-standardised (world) incidence rates; direct comparison

Analysis for children (0-14 years): 

Analysis for children (0-14 years)

Crude and age-standardised incidence rates; contaminated regions - children: 

Crude and age-standardised incidence rates; contaminated regions - children 95% CI‘s (Poisson) for the crude rates regression line for the standardized rates

Crude and age-standardised incidence rates; control regions - children: 

Crude and age-standardised incidence rates; control regions - children 95% CI‘s (Poisson) for the crude rates regression line for the standardized rates

Age-standardised incidence rates;direct comparison - children: 

Age-standardised incidence rates; direct comparison - children

Standardised Incidence Ratios (SIR): 

Standardised Incidence Ratios (SIR)

Standardised incidence ratios with 95% CI‘s;contaminated / control regions - adults: 

Standardised incidence ratios with 95% CI‘s; contaminated / control regions - adults

Standardised incidence ratios with 95% CI‘s;contaminated / control regions - children: 

Standardised incidence ratios with 95% CI‘s; contaminated / control regions - children

Standardised incidence ratios with 95% CI‘sfor three time periods – adults [pI: 1980-86, pII: 1987-92, pIII: 1993-97]: 

Standardised incidence ratios with 95% CI‘s for three time periods – adults [pI: 1980-86, pII: 1987-92, pIII: 1993-97]

Standardised incidence ratios with 95% CI‘sfor three time periods – children[pI: 1980-86, pII: 1987-92, pIII: 1993-97]: 

Standardised incidence ratios with 95% CI‘s for three time periods – children [pI: 1980-86, pII: 1987-92, pIII: 1993-97]

Slide43: 

Doses received by the population 95% of the additional life-time dose is received in the first 10 years after the accident (1986-1995). Mean additional dose - without thyroid dose - over 10 years: - in the control regions: 0.1 mSv (0.01 mSv/year) - in the contaminated regions: 7.2 mSv (0.72 mSv/year) - yearly dose (nat. and med.): 2-2.4 mSv - x-ray chest: 1.5 mSv - computer tomography: 10-20 mSv

Slide44: 

Conclusions Leukaemia incidence rates in Belarus, Russia, and the Ukraine are similar in the contaminated and the control regions. A slightly increasing secular trend can be observed. Its increment in the contaminated regions is in line with the control regions and other European countries. There is no indication of an increased risk for leukaemia in the general population as a result of the ChNPP Accident. This does not contradict the current radiobiological knowledge that cancer, especially leukaemias, can be induced by ionizing radiation.

Slide45: 

Conclusions Taking into account the known risk-coefficients and latency periods, it is highly improbable that a radiation-related increase in leukaemia or in the less radio-sensitive solid tumours will become obvious in the future. This is not true for thyroid cancer incidence rates, which have been proved to have increased since the beginning of the 1990s as a result of the comparatively high organ-specific doses through short-lived radio-iodine. The fear and apprehension caused by the over-estimation of the radiation risks create a continuous stress situation and add to the present detrimental health condition of the population. It is therefore of utmost importance to communicate not only the results but also the reliability of the study and the soundness of the data to the affecte people.

Slide46: 

Outlook No increase in the leukaemia incidence rates in the general population. Very small increases of rare sub-types of leukaemia or increases in small population groups that were exposed to higher doses would not be statistically detectable in a cohort study design. Such small effects of low radiation doses would, if at all existent, become evident only in a carefully designed case-control setting.

Slide47: 

Last, not least...

Slide48: 

Many thanks to all colleagues that I have had the pleasure to work with during the past years to all those whom I have never met but whose work has contributed in any way especially to Aleksandr Korelo for helping with the joint data analysis

Slide52: 

Gross National Product in By, Ru, Ua* *data of the United Economic Commission for Europe (UNECE)

Physiological Haematopoiesis: 

Physiological Haematopoiesis

Slide54: 

Childhood leukaemia in Belarus – the 208 problem black line: RIHBT, ICD 204-208 gray line: RIHBT, ICD 204-207 broken line: Belarusian Childhood Cancer Reg., ICD 204-207 graphic by Elke Nekolla, BfS