Epidemiology Principles And Practices

Question 1   (14 marks)

1. Calculate and compare the crude and age-specific incidence rates of prostate cancer per 100,000 men between the two cities. (4 marks)
2. According to your results in Q1-a, is the comparison of crude rates valid in consideration of the population structures in the two states? Why or Why not? (Hint: calculate and compare the age structures of the populations in the two cities) (2 marks)
3. Calculate and compare direct standardised incidence rates (per 100,000 men) of prostate cancer for men living in City A and in City B using the given standard population (last column of the table). Discuss the differences in the results of crude and standardised rates of the two cities. (5 marks)
4. How does the risk of developing prostate cancer vary by age within each of the two cities? (Calculate appropriate measures to quantify the variation). Based on your results, is age a risk factor of prostate cancer for both cities? Interpret your results briefly (3 marks)

Question 2  (6 marks)

In 2000, 5,458 women were screened for cervical cancer and 92 were found to have CIN 3 stage or above (diagnostic of carcinoma of the cervix or carcinoma-in-situ). The women who did not have cervical cancer were re-screened in 2005 and another 60 cases were diagnosed. 

1. What was the prevalence of cervical cancer in 2000 and 2005? (2 marks)
2. What was the incidence of cervical cancer in these women? Is this a measure of cumulative incidence or incidence rate? Why? (2 marks)
3. Assume that, on average, each of the 60 women who were diagnosed with cervical carcinoma did so half-way through during the five-year period.

What is the incidence rate (incidence density) of cervical cancer in these women during the five years? (2 marks)

Question 3 (4 marks)  

Classify the following scenarios according to epidemiological study type. In your answer nominate one of the epidemiological study designs listed below and also provide 2 reasons for your choice of study design in each scenario.

1. A study compared changes in ovarian cancer mortality rates (Standardised Mortality Ratios) and average family size over time in England and Wales and the results are shown in the graph below. (2 marks)
2. A total of 825 insulation workers employed between 1941 and 1944 were identified from the personnel records of three large insulation manufacturing plants in the south-eastern United States in 1975. During the period 1941-1975, 26 deaths from lung cancer were discovered among the workers. Only six lung cancer deaths, however, were reported among a comparable group of 700 co-workers who did not work with insulation during the same time period. The investigators had postulated that exposure to the insulation material increases the risk of lung cancer. (2 marks)

Question 4   (6 marks) 

Find the demographic and health statistical data from WHO's databank ('Mortality and global health estimates': http://www.who.int/research/en/; and 'Global Health Observatory Data Repository': http://apps.who.int/gho/data/node.country) and complete the following table (2 marks). Compare the population data and comment on the public health status among the three selected countries and interpret their public health implications briefly (word limit: 200) (4 marks).