Question

A total population of 4,185 people are being observed in a five-year study measuring incidence of prostate cancer.

• 38 prostate cancer cases were confirmed at the end of year 1. •

17 additional cases were confirmed and 5 men had withdrawn from the study at the end of year 2. •

52 additional cases were confirmed at the end of year 3. •

19 additional cases were confirmed and 10 men had withdrawn from the study at the end of year 4. •

30 additional cases were confirmed and 5 men had withdrawn from the study at the end of year 5.

What is the incidence rate of prostate cancer in this population, expressed in terms of 1000 person-years?

Answer 1

The incidence rate of prostate cancer in this population, expressed in terms of 1000 person-years is 7.469

Explanation:

Consider the provided information.

It is given that 38 prostate cancer cases were confirmed at the end of year 1 and the total population was 4,185.

As we need to find the incidence rate of prostate cancer in this population, expressed in terms of 1000 person-years, thus 4185/1000 = 4.185

Thus, the incident rate is: Number of new case/ population of study in 1000.

`(38)/(4.185)=9.080`

17 additional cases were confirmed and 5 men had withdrawn from the study at the end of year 2. That means total population is 4185-5=4180

Thus, the incident rate is:

`(17)/(4.180)=4.067`

52 additional cases were confirmed at the end of year 3.

Thus, the incident rate is:

`(52)/(4.180)=12.44`

19 additional cases were confirmed and 10 men had withdrawn from the study at the end of year 4.

Thus, the incident rate is:

`(19)/(4.170)=4.556`

30 additional cases were confirmed and 5 men had withdrawn from the study at the end of year 5.

Thus, the incident rate is:

`(30)/(4.165)=7.203`

The average expressed in terms of 1000 person-years

`(9.080+4.067+12.44+4.556+.203)/(5)=(37.346)/(5)=7.469`

Hence, the incidence rate of prostate cancer in this population, expressed in terms of 1000 person-years is 7.469