The Biostatistics (Math Problem Sample)

Practical assignment 5
MPH 621
Spring 2021
1 The Oakland Nutrition Program enrolled 500 children in January 2012. All of these children were screened for obesity at the beginning of the year and 66 were found to have overweight problems. When the same 500 children are screened again in January 2013, 80 are found to have overweight problems. (2 points)
* What was the prevalence of overweight problems in the Oakland Nutrition Program in 2012? (0.5 points)
Prevalence= Number of people with the characteristic of interestTotal number of people in the population
Prevalence of overweight in 2012=66500*100=13.2%
* What was the prevalence of overweight problems in the Oakland Nutrition Program in 2013? (0.5 points)
Prevalence of overweight in 2013=80500*100=16%
* What is the risk of developing overweight problems over the period of time between the January of 2012 and January of 2013 in this group of Nutrition Program children? And what type of measure of disease occurrence it is? (1 points)
Risk, also known as incidence proportion or cumulative incidence, is the measure of proportion of disease-free individuals in a population that contract a disease or medical condition in a certain time interval. In this case, our incidence rate is
Risk=Number of new casesSize of the population at the start period
Risk=80-66500*100=2.8%
2 You want to know more about colorectal cancer rates in the United States and the associated risk factors. For your investigation, you decide to start by using “descriptive epidemiology” and describe the disease in term of person, place and time (2 points).
For questions a and b: Go to the “SEER EXPLORER” webpage of the Surveillance, Epidemiology and Ends Results Program (SEER) of the National Cancer Institute:
SEER*Explorer (cancer.gov)
* Examine the cumulative incidence rates and adjusted cumulative Incidence rate for colorectal cancer over time in the U.S. between 2000 and 2015.(1 point)
* Select Get Started
* Select Colon and Rectum from “Cancer Site”
* Select “All races”, “Both sex” and “All ages”, and “All Stages”.
* Select “observed Incidence Rate” and “Adjusted incidence Rate”
* Select “Table”. Display “Rate”
Report the “Age-adjusted rates” and “Observe incidence Rate ” for “colon and rectum” for 2000 and 2015.
Describe the incidence rate trend over time in the U.S. for colorectal cancer.
Using the information provided in the cancer.gov website, it is clear that over time from 2000 to 2017, the incidence rate of colorectal cancer has been following a downward trend. The incidence rate in 2017 is much lower compared to the one in 2000. Hence indicating a decline in the risk of contracting colorectal cancer.
What is the incidence rate in 2000? And in 2015?
The Incidence rate of colorectal cancer in 2000 was recorded to be 55.8, while in 2015 it was recorded to be 38.4
What is the age adjusted rate in 2000? And in 2015?
The incidence rate of colorectal cancer in 2000 by age is
Ages <15

_

Ages 15-39

3

Ages 40-64

52.5

Ages 65-74

231.1

Age 75+

390.2

All Ages

55.8

The incidence rate of colorectal cancer in 2015 by is age is
Ages <15

0.3

Ages 15-39

5

Ages 40-64

48.5

Ages 65-74

131.5

Age 75+

222.7

All Ages

38.3

Calculate the Cumulative Incidence over the period of 2000-2015
The cumulative incidence of the period of 2000-2015 is the sum of the incidence rate for each of the years between and including 2000 and 2015.
Year

IR

2000

55.8

2001

55.2

2002

54.1

2003

52.4

2004

50.7

2005

49.2

2006

47.9

2007

47.3

2008

46.1

2009

44.2

2010

42.2

2011

41

2012

39.8

2013

39

2014

39.3

2015

38.4

Sum

742.6

Therefore, the cumulative incidence rate of the period 2000-2015 is 742.6 per 100, 000 people
* Change the setting of the sex once to Male and once to Female and setting of the Race once to White and once to Black and calculate the incidence rates for colorectal cancer for women and men according to race/ethnicity (Black and White only) (1 points)
What are the incidence rates for colorectal cancer for women and men according to rac