Epidemiology mathematical equations

Calculations

Problem #1

Fill in the blank spaces in the chart: Within this assignment, imagine that you have been hired as a new hospital infection control manager and are immediately welcomed by the chief of staff and house super who have grave issues regarding a recent state of nosocomial infections within the facility and they need some assistance determining the statistics related to the prevalence and incidence of the infections to get a better grasp of what clinical and countermeasures need to be taken at the hospital next.

(Population = 82,438,000)

Cause of Admission	Number of admits	Proportional Case Ratio (%)	Cause-specific rate per 100,000
Accidents and adverse effects	26,526
Malignant neoplasms	22,228
HIV infection	21,747
Diseases of the heart	15,822
Homicide and legal intervention	12,372
Suicide	12,281
Chronic liver disease and cirrhosis	4,449
Cerebrovascular diseases	3,343
Diabetes mellitus	2,211
Pneumonia and influenza	2,203

Problem #2

Calculate the Relative Risk: An uptick in attempted suicides in teen boys has interested the State Health authorities and they are looking for some information on the data the hospital has received in the past calendar year. The common exposure factor here is a history of parental abuse.

	Suicide Attempt	No Suicide Attempt
History of Parental Abuse
No History of Parental Abuse

Those who reported parental abuse:

14 had attempted suicide

9 had not attempted suicide

Those who had not reported parental abuse:

49 had attempted suicide

149 had not attempted suicide

Calculate the Relative Risk

Problem #3

Calculate the prevalence: You are a physician who practices medicine in HappyVille, a community of 100,000 persons. During 2009, there were 1,000 deaths from all causes. All cases of cardiovascular disease were identified, and they totaled 300. During 2009, there were 60 deaths from cardiovascular disease. The prevalence of cardiovascular disease in HappyVille in 2009 was:

Problem #4

Calculate the 10-day cumulative incidence: Influenza is spread by close contact between an infected person and an uninfected person who has not had the infection and therefore is at risk.

Imagine that there are 10 students living on your dorm floor, which is the second floor of the building. One of the students has returned on the evening of Sunday, October 3rd, from a weekend away at a friend’s wedding. On the morning of Tuesday, October 5th, he shows all the typical symptoms of influenza, including a mild fever and sore throat. By the end of the following Sunday, October 10th, four other students on the floor are showing identical symptoms. What is the cumulative incidence rate for influenza for the period October 1 through October 10 on the second floor of the dorm? Your answer should be specific.

The ten-day cumulative incidence for the second floor of the dorm is:

Problem #5

Calculate the prevalence per thousand: 125 people out of 5000 have food poisoning. Determine the disease prevelance per 1000 people. (Show your work).

SOLUTION: Prevalence per 1000 =

Problem #6

Calculate the incidence rate: 4,875 healthy people are tracked over a two-year period. Over that two-year period, 75 of those people develop a particular disease. Determine the incidence rate of disease over the study period? Show all your work.

Problem #7

Calculate the rate difference and provide an interpretation of the result: You conduct a study to assess the association of traffic accidents to the use of cellular phones while driving. Your study reveals that per 10,000 miles, the incidence of traffic accidents for people that were using their cellular phones is 11.1; and the incidence of accidents for people not using their cellular phones is 8.6. Detrermine the difference between accident rates for people that were driving and using their cellular phone versus those that were not using their phone while driving. Then write a paragraph or two explaining your findings or results.

Problem #8

Calculate category statistics: Autism is a disability that is characterized by a severely decreased ability to engage in communication and social interaction. A study was undertaken to establish the prevalence of Autism in a community. Data from this study are reported below:

Children Diagnosed With Autism per Age Group
Age Group	Children With Autism
3–5	193,479
6–10	175,417

Calculate the prevalence rate of autism for the two age categories.
Calculate the prevalence to a rate per 1,000.

Problem #9

Complete the following calculations and provide an explanation of your findings: A study of hypertension begins with 1,000 men (ages 40–45). Of the 1,000 men, 50 are already hypertensive. The remaining 950 are tracked over the span of five years, during which time 64 additional men develop hypertension. (Assume there is no loss to follow-up or death due to competing risks).

Determine the prevalence of hypertension at the beginning of the study.
Calculate the five-year incidence proportion (risk) of hypertension.
Calculate the incidence rate of hypertension in the cohort with and without an actuarial adjustment. Did the actuarial adjustment make a difference? Explain your answer.

Problem #10

Determine if the prevalence will increase or decrease: Write a few sentences that explain the effect that the following situations would have on a population (assume other dynamics of the population do not change).

Immigration of cases (unhealthy persons) into the population.
Emigration of cases (unhealthy persons) out of the population.
Emigration of healthy persons out of the population.
Immigration of healthy persons into the population.
Increase in the fatality rate among the cases (unhealthy persons).

Problem #11

Complete the calculations:

Population Size	255,078,000
Approximate number of live births	4,065,014
Number of deaths (all ages)	2,175,631
Approximate number of deaths in infants under 1 year of age	34,553

Compute the birth rate per 1,000.
Compute the overall death rate per 100,000.
Compute the infant mortality rate per 1,000.

Problem #12

Review the chief resident’s conclusion on the following data and make a comment regarding the validity of the conclusion (include reasons why or why not): Your local hospital reports some data on accidents presenting in their emergency room and has broken down the data for 82 patients who have presented to the emergency department in the past year (use the following table):

Age in Years	Number of Accidents
0–2
3–5
6–14	18
15–21
22–31
32–41
42–51
52–61
62 and over	21

Based on this data, the chief resident has concluded that “the data concludes that the age group containing persons age 62 and older are the most prone to accidents.The category that holds the second greatest risk is 6–14 year olds.”

Comment on the chief resident’s misinterpretation of the data:

Problem #13

The following vital statistics are demonstrated within a population:

Total mid-year population = 25,000.

Population 65+ years old = 2,500.

Number of live births = 300.

Total deaths (for all causes) = 250.

Deaths in infants less than 1 year old = 3.

Deaths in persons 65+ years old = 75.

Complete the following calculations: