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Ora Paltiel, MD, MSc

Ora Paltiel, MD, MSc Braun School of Public Health & Community Medicine Hebrew University of Jerusalem Hadassah Medical Organization Israel. Epidemiological Reasoning Using Cancer Statistics. Or, how to use descriptive statistics to raise hypotheses. Validity of data Reporting Confounding

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Ora Paltiel, MD, MSc

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  1. Ora Paltiel, MD, MSc Braun School of Public Health & Community MedicineHebrew University of Jerusalem Hadassah Medical Organization Israel

  2. Epidemiological ReasoningUsing Cancer Statistics Or, how to use descriptive statistics to raise hypotheses

  3. Validity of data Reporting Confounding Effect modification Using Descriptive Data Burden of Disease Planning Hypothesis raising Measuring progress Issues to be discussed

  4. What are the objectives of epidemiology? 1. To determine the extent of disease (states of health) and/or behaviors in the community. 2. To identify the etiology or the cause/s of a disease and the risk factors - that is, factors that increase a person’s risk for a disease. 3. To study the natural history and prognosis of disease.

  5. Objectives of epidemiology 4. To evaluate new preventive and therapeutic measures and new modes of health care delivery. 5. To provide the foundation for developing public policy and regulatory decisions relating to public health problems.

  6. “When we measure, we know better” - Center for Disease Control (CDC), Atlanta, Georgia,USA

  7. The epidemiological tool-box

  8. Kaposi sarcoma in New York

  9. The context of disease reporting

  10. Lowest cancer death rate In the Former Yugoslav Republic of Macedonia, only 6 people per 100,000 of population die from cancer each year

  11. Lifetime risk of developing breast cancer, 1940-1987

  12. Lifetime risk of developing breast cancer, 1940-1987 cont’d YEAR ONE IN…. 1940 20 1950 15 1960 14 1970 13 1980 11 1987 9 Source: American Cancer Society, 1991

  13. Descriptive epidemiology - hypothesis raising rarely provides enough evidence for causation • Person: characteristics for study include: • Age • Gender • Religion • Marital status • Ethnicity • Occupation • Socio-economic class • Heredity vs. Environment

  14. Age-specific rates of Breast Cancer Mortality

  15. Population Pyramids 1998 Russian Federation Israel

  16. Trends of Cervical Cancer Mortality in Europe and North America

  17. Age-standardized cervical cancer death rates (and 95% confidence intervals) per 100 000 women in urban Canada by neighbourhood income quintile from 1971 to 1996. Q1 = richest Q5 = poorest.

  18. Place and time Time trends - raise hypotheses regarding environmental factors or results of medical care Geographic variation - on small + large scale, environmental  genetic factors Study of migrants: important for separating environmental from genetic factors

  19. Numbers of cases of cancer at 16 anatomical sites in developed and in developing countries, with relative ranks

  20. Lung Cancer Mortality for Women 1998, ASR/100000

  21. Lung Cancer Mortality for men 1998, ASR/100000

  22. Age-adjusted cancer death rates, males by site, US, 1930-1996

  23. Age-adjusted cancer death rates, females by site, US, 1930-1996

  24. Estimated annual percent changes in mortality from all types of cancer in the US over 2 periods 1973-1990 and 1991-1995, according to age group

  25. Place and time cont’d Japanese colon cancer incidence: JapanHawaiiCalifornia -  rate is affected by age at immigration - for breast cancer: 2 generations required for  rate High Intermediate Low

  26. Biases in migrant studies 1) Different reporting 2) Different diagnostic criteria 3) Migrants are selected group

  27. Where does evidence come from? Clinical observation Descriptive data Hypothesis raising

  28. Hypothesis raising Clinical observation Descriptive data Analytical studies Hypothesis testing

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