This document discusses life tables and their importance. It provides a brief history of life tables, noting their development by John Graunt and Edmund Halley. Life tables are useful for estimating survival rates, mortality rates, and other vital statistics. They allow calculation of life expectancy and comparison of mortality between populations. The document then describes how to construct a life table and provides examples of their use in clinical medicine using the Kaplan-Meier method.

1. LIFE TABLEDr. Priyadarshini. CI M.D.ICM, MMC

2. INTRODUCTION Described as the ‘Biometer’ of the population by William Farr. Means of describing mortality, survival and other vital events in the population.

3. HISTORY OF THE LIFE TABLE

4. HISTORY OF THE LIFE TABLE John Graunt(1620-1674) - Natural and Political Observations Made upon the Bills of Mortality (1662)

5. Graunt’s Life Table

6. HISTORY OF THE LIFE TABLE

7. HISTORY OF THE LIFE TABLE Edmund Halley (1656 – 1742) - ‘An estimate of the Degree of the Mortality of Mankind drawn from the curious Table of the Births and Funerals at the city of Breslaw’

8. Halley’s Life Table

9. IMPORTANCE OF LIFE TABLE- No. of survivors At 5 years, the no, of children likely to enter primary school At 15 years, no. of women entering fertile period At 21 years. no. eligible for voting- No. likely to die after life insurance or after joining service to budget for payment towards risk or pension

10. IMPORTANCE OF LIFE TABLECalculation of expectation of life and comparison of mortality among communities

11. Population studies

12. Survival rate after treatment- Analysis by causes of death

13. CONSTRUCTION OF A LIFE TABLEPrerequisites1. Population living at all individual ages in a selected period2. No. of deaths that occurred in these ages during the selected period

14. Standard Notations

15. Construction of Life Table1.2.3.

16. Construction of Life Table4.5.6.7.

17. DECREMENT TABLE The column of deaths or living can be split and analysed for new characteristics.

18. LIFE TABLE IN CLINICAL MEDICINEKAPLAN-MEIER METHODMost commonly used approach to survival analysis in medicine. Also called as the Kaplan-Meier life table method or the product-limit method. Actuarial method used if there are large numbers of subjects but the Kaplan-Meier method more advantageous if the numbers of subjects are small.

19. KAPLAN-MEIER METHODThe actuarial method calculates survival rates based on fixed intervals whereas in the Kaplan-Meier method the intervals are uneven. Here, the deaths are not conceived of as occurring during an interval. Rather, they are seen as instantaneously terminating one interval and beginning a new interval.

20. KAPLAN-MEIER METHODDataTiming of Deaths in 4 subjects: 0.8, 3.1, 5.4, 9.2 monthsTiming of loss to follow-up or censorship in four subjects: 1.0, 2.7, 7.0, 12.1 months

21. KAPLAN-MEIER METHODTabular Representation of Data

22. KAPLAN-MEIER METHODGraphic Representation of the Data

23. KAPLAN-MEIER METHOD Graphic Representation of comparison of two groups

24. TESTS OF SIGNIFICANCE Differences between actuarial survival curve – t-test and z-test Differences between Kaplan-Meier curves – Logrank test

25. LOGRANK TEST

26. COX REGRESSION (POPULATION HAZARDS MODEL) Adjustment for potential confounding variables.

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