1. Topic 5: Rates and Standardization Modified from the notes of A. Kuk P&G pp. 66—95

2. Demographic Data Size of population and its composition by gender, race, age etc

3. Vital Statistics Vita --- life Tell a story of life with numbers so that vital services can be provided --- food, lodgings, health, water, etc

4. Births Natural Increases Marriages Divorces Diseases Deaths Complex and massive story because we often need to deal with whole countries.

5. Describe health status of a population Spot trend Make projections Planning Set policy Compare groups Want to be able to:

6. Provisional statistics USA 12 months ending in April (millions)199319941995 Live births4.0754.0173.966 Deaths2.2072.2802.297 Increase1.8681.7371.669 Marriages2.3522.3302.345 Divorces1.2031.1851.179 Infant deaths * 33,70032,40031,100

8. Death rate increasing?

9. “Crude” rate, single number, summary allows for standardization makes comparisons more meaningful

10. State of Massachusetts in 1992Number Population 6,060,943 Live births87,202 Deaths: Total53,804 Under 1 year569 Crude birth rate per 1000 persons per year Crude death rate per 1000 persons per year Infant mortality rate per 1000 live births per yr

11. Rate a Per 1,000199319941995 Live births15.915.515.2 Fertility rate b 69.067.966.8 Deaths8.68.8 Increase7.36.76.4 Marriages9.29.0 Divorces4.74.64.5 Infant deaths c 8.38.27.9 a=pop., b=women 15-44, c=live births

14. Crude rate answer all questions? StatusPop n Impair’sRate /100,000 Employed98,9175525.58 Unemployed7,462273.62 Not in labor force 56,7783686.48 Total163,1579475.80

15. Therefore it is better to be “employed” than “not in the labor force” as far as hearing is concerned Confounders?

16. Age distribution EmployedNot in labor force AgePop n PercentPopnPercent 17-4467,98768.720,76036.6 45-6427,59227.915,10826.6 65+3,3383.420,91036.8 Total98,917100.056,778100.0

17. Age Composition of Population Age Pop n ImpairsRate /1000 17-4494,9304414.65 45-6443,8573087.02 65+24,3701988.12 Total163,1579475.80

18. Age Specific Impairment Rates Currently employed Age Pop n ImpairsRate /1000 17-4467,9873465.09 45-6427,5921796.49 65+3,338278.09 Total98,9175525.58

19. Age Specific Impairment Rates Not in labor force Age Pop n ImpairsRate /1000 17-4420,760803.85 45-6415,1081177.74 65+20,9101718.18 Total56,7783686.48

20. Age Specific Impairment Rates Age Employed /1000 Not in labor force /1000 17-445.093.85 45-646.497.74 65+8.098.18 Total5.586.48

21. Can we capture what is happening with a single number? Problem caused by different age profiles. Standardize Direct Indirect (skipped)

22. Direct method of getting rid of age confounder is to standardize the age distribution and apply the appropriate age specific rates. Select a standard age distribution. Logical choice is the total population

23. For Currently Employed Age Pop n Rate /1000 Expected Impairs 17-4494,9305.09483.2 45-6443,8576.49284.6 65+24,3708.09197.2 Total163,157965.0

24. For those not in labor force Age Pop n Rate /1000 Expected Impairs 17-4494,9303.85365.5 45-6443,8577.74339.5 65+24,3708.18199.3 Total163,157904.3

25. Crude rate Not in labor force > Employed Age adjusted Not in labor force < Employed Remember 1.This is a construct. 2.Choice of standard distribution is arbitrary.

28. Age-Adjusted Cancer Death Rates, Males by Site, US, 1930-1996 Adjusted using the U.S. population in 1940 as the standard distribution

29. Age-Adjusted Cancer Death Rates, Females by Site, US, 1930-1996

30. When to use adjustment: Check that the age-specific rates follow more or less the same trend for all the populations to be compared. Is there a confounder? Age? Sex?

32. go so no