The following table describes hypothetical age-specific rates of heart disease in India and the United States in 2009. Also included are hypothetical age distributions for the two countries and the entire world population.
|
Age Group
(in years)
|
% of Population in Age Group
|
Heart Disease Rate per 100,000 person-years
|
|
INDIA
|
U.S.A.
|
WORLD
|
INDIA
|
U.S.A.
|
|
60%
|
30%
|
50%
|
50
|
75
|
|
30-55
|
30%
|
40%
|
30%
|
80
|
150
|
|
> 55
|
10%
|
30%
|
20%
|
120
|
400
|
Calculate the crude rate of heart disease for each of the two countries. Suppose that you want to compare the rate of heart disease in India to that in the United States. You know that age is an important risk factor for heart disease. Examine the age distribution of each country's population.
Should you use the two crude rates to compare the two countries? Why or why not?
Calculate an age-adjusted rate for heart disease in each country. Use the age distribution of the entire world as your standard.
Based on these answers, would you say that the age differences between India and the United States account for the entire difference in crude heart disease rates between the two countries? Why or why not?