Epidemiology Assignment: Risk Factors and Study Analysis

This document presents a comprehensive solution to an epidemiology assignment, addressing various aspects of epidemiological study design and data analysis. The assignment focuses on a prospective cohort study investigating the relationship between dietary niacin intake and the incidence of hearing loss in men. The solution provides answers to multiple-choice questions involving calculations of absolute and relative risk, risk differences, and odds ratios. It also covers the interpretation of epidemiological concepts such as confounders, effect modifiers, and recall bias. Furthermore, the assignment includes calculations of crude and age-specific death rates, standardized mortality ratios (SMR), and attack rates within a foodborne illness outbreak scenario. The solutions demonstrate the application of epidemiological principles to assess risk factors, evaluate study designs, and interpret statistical findings in public health contexts. The answers provided showcase a clear understanding of epidemiological concepts and their application to real-world health scenarios, including risk assessment, study designs, and statistical analysis.

Running head: EPIDEMIOLOGY
EPIDEMIOLOGY ASSIGNMENT
Name of the Student
Name of the University
Author’s Note:

1EPIDEMIOLOGY
Answer to the question number 1:
Prospective Cohort Study
Answer to the question number 2:
Absolute Risk = (755/ 7550) X 100
= 10 %
Answer to the question number 3:
Absolute Risk = (378/ 7570) X 100
= 5.0 % (After rounding off)
Answer to the question number 4:
Relative Risk
Answer to the question number 5:
Relative Risk = (Absolute risk in lowest quintile/ Absolute risk in Highest quintile)
= (10/ 5)
= 2.0
Answer to the question number 6:
Absolute risk difference = Absolute risk in lowest quintile - Absolute risk in Highest quintile
= (10 % - 5 %)
= 5 %
Hence, the answer is 0.05 [5.0 %]
Answer to the question number 7:

2EPIDEMIOLOGY
The risk of developing Hearing loss is “x-times” higher in men with the lowest intake of
dietary Niacin compared to men with the highest intake of dietary Niacin.
Answer to the question number 8:
The attributable risk percent or fraction.
Answer to the question number 9:
Confounder
Answer to the question number 10:
Effect Modifier
Answer to the question number 11:
Total number of people = (2542+ 3267+ 2725+ 1403) = 9937
Total number of death = (6+ 17+ 25+ 122) = 170
∴Crude death rate in population A per 1000 = (170/ 9937) X 1000
= 17.1
Answer to the question number 12:
Age- specific death rate for 0 -20 years age group (per 1000) in Population A,
= (6 / 2542) X 1000
= 2.4 (After rounding off)
Answer to the question number 13:
BOTH a and c are correct.
Answer to the question number 14:

3EPIDEMIOLOGY
Direct standardisation.
Answer to the question number 15:
National mortality rate for the age group of 0 – 20 = 3.3
∴Expected number of deaths within the 0-20 age group = (3.3 / 1000) X 2542
= 8.4 (After rounding off)
Answer to the question number 16:
Expected death in Population A according to the national mortality rate in different age
group,
0-20 2.4
21-49 5.2
50-69 9.2
70+ 87.0
Total 103.7
Total number of death according to the national mortality rate, = 53.3
∴ Standardised mortality ratio (SMR) = (103.7 / 53.3) = 1.9
1.9 is closest to the 1.6, hence the answer is 1.6
Answer to the question number 17:
Absolute risk of death = (23/ 444) X 100 = 5.2 % (After rounding off)
Hence, the answer is 0.052 (5.2%)
Answer to the question number 18:
Absolute risk of death = (41/ 445) X 100 = 9.2 % (After rounding off)
Hence, the answer is 0.092 (9.2%)
Answer to the question number 19:

4EPIDEMIOLOGY
Absolute risk reduction = (0.092 – 0.052) = 0.04
Hence, the answer is 0.04 (4%)
Answer to the question number 20:
Relative risk = (0.052 / 0.092)
= 0.56
Answer to the question number 21:
Relative Risk Reduction = (1- Relative Risk)
= (1 – 0.56) = 0.44
Hence the answer is 0.44 (44%)
Answer to the question number 22:
One death per individual in case of restrictive strategy = (444/ 23) = 19.3
One death per individual in case of liberal strategy = (445/ 41) = 10.85
The number of people with severe upper GI bleeding that need treated with a restrictive
transfusion (compared with a liberal transfusion) to prevent 1 extra death over a 6 week
period is closest to 10.
Answer to the question number 23:
Case-control study
Answer to the question number 24:
Odds ratio
Answer to the question number 25:

5EPIDEMIOLOGY
Heart attack No Heart Attack
Exposed 220 150
Not Exposed 1000 1050
∴Odd’s Ratio = (220/ 1000) / (150/ 1050) = 1.54
Hence, the answer is 1.5
Answer to the question number 26:
The odds of being exposed to high levels of work place stress in the past is higher in people
who experience a Heart attack compared with those who do not.
Answer to the question number 27:
Recall bias
Answer to the question number 28:
Collider
Answer to the question number 29:
Effect modifier
Answer to the question number 30:
Prospective cohort study
Answer to the question number 31:
Control the Epidemic and communicate the results
Answer to the question number 32:
Describe the epidemic in terms of person, place and time
Answer to the question number 33:

6EPIDEMIOLOGY
Attack rate of those who consumed beverages = (179/ 264) X 100 = 67.8 %
Attack rate of those who did not consumed beverages = (22/ 50) X 100 = 44 %
Hence, the answer is 67.8% and 44.0% respectively.
Answer to the question number 34:
Attack rate of those who consumed egg salad = (176/226) X 100 = 77.87 %
Attack rate of those who did not consumed egg salad = (27/ 73) X 100 = 36.98 %
Hence, the answer is 77.9% and 37.0% respectively.
Answer to the question number 35:
Perform a cross-tabulation analysis of the beverage and egg salad