Epidemiology & Biostatistics (EPID6001) Assignment

Running head: EPIDEMIOLOGY AND BIOSTATISTICS 1
Epidemiology and Biostatistics
Student’s Name
University Affiliation

EPIDEMIOLOGY AND BIOSTATISTICS 2
Question 1
Incidence portrays information about the risk of developing a disease while prevalence shows
how the disease spreads (Spiegelman & Hertzmark, 2005). For the case of disease x, it will have
high prevalence and incidence. This is because the disease is incurable so the number of people
who are affected remains very high. When the incidence of disease x is constant, for the time of
the disease, prevalence is the product of the disease incidence plus average disease duration.
Therefore, when the incidence increase, the prevalence also increases
Question 2
a) Cumulative frequency of the disease is given by 15/500 = 0.03 or 3%
b) Incidence rate of the disease is given by = (No. of new cases /person-time at risk)
15/1000 = 0.015 or 1.5%
c) Cumulative frequency of the disease is twice its incidence rate.
Question 3
a) Prevalence of HBP at the age of 55years is 300/3000 = 0.1 or 10%
b) Prevalence of HBP at the age of 65 is 700/2700 = 0.26 or 26%
c) Cumulative frequency of HBP among the women is 700/3000 = 0.23 or 23%
d) Number of person-times at risk of contracting HBP within 10 years
is 3, 000+2300 at risk at the end of 10 years /2) *10years
(5300/2)*10= 26500 person-year of risk
e) Incidence rate of HBP among women is 700/26500= 2.645%

EPIDEMIOLOGY AND BIOSTATISTICS 3
Question 4
a) Period prevalence of hypertension is 1500/30000= 5%
b) Cumulative incidence of hypertension is 600/30000= 0.02
c) Incidence rate of hypertension is 600/36000= 1.7%
d) Cumulative incidence of hypertension is much higher compared to the incidence rate due
to an increase in population and the number of hypertension incidences.
Question 5
The study report with relative risk of 1.8 at 95 percent confidence interval of 1.6–2.0 for the
link between alcohol consumption and cancer is ideal since it shows precise plus statistically
significant estimate because the CI is narrow and doesn’t include 1.0 (Jekel et al., 2007). Also
the 1.8 RR indicates an 80% increases relative risk of cancer due to alcohol consumption.
Question 6
a)
Alcohol consumption group
Never Occasional Light Medium Heavy
At
danger
subjects
466 1845 2544 2042 832
No. of
deaths
126 439 654 512 62