EPIDEMIOLOGY MCQs With Key - (Community Medicine)

1. While investigating a point source epidemic it was found that 120 students ate five different foods (meat burgers, fried fish, steak, rice and fruit salad). The relative risk was calculated for all those five foods. It was concluded that fish was not responsible for this epidemic. The relative risk of fish is:
a. 0.7
b. 1.2
c. 1.7
d. 3.0
e. 7.0

Key: True: a

In a prospective study of the relationship between oral contraceptive use and the subsequent risk of developing endometrial cancer, a cohort of 1000 women were followed for 5 years. The results were as follows:

A 245
B 75
C 50
D 630
A + C = 295 B + D = 705 n = 1000
2. What is the incidence rate (absolute risk) of endometrial cancer among who didn’t use oral contraceptives?
a. 630 / (50 + 630)
b. 75 / (245 + 75)
c. 50 / (50 + 630)
d. 245 / (245 + 75)
e. Insufficient data

Key: True: c 50/(50 + 630)

In a prospective study of the relationship between oral contraceptive use and the subsequent risk of developing endometrial cancer, a cohort of 1000 women were followed for 5 years. The results were as follows:

A 245
B 75
C 50
D 630
A + C = 295 B + D = 705 n = 1000
3. What was the incidence rate (absolute risk) of endometrial cancer among women who used oral contraceptives?
a. 630 / (50 + 630)
b. 75 / (245 + 75)
c. 50 / (630 + 50)
d. 245 / (245 + 75)
e. Insufficient data

Key: True: d 245/(245 + 75)

In a prospective study of the relationship between oral contraceptive use and the subsequent risk of developing endometrial cancer, a cohort of 1000 women were followed for 5 years. The results were as follows:

A 245
B 75
C 50
D 630
A + C = 295 B + D = 705 n = 1000
4. What is the incidence rate (absolute risk) of endometrial cancer among women who used oral contraceptives in person-years? If the study was carried out for five years.
a. 630 / (680 x 5)
b. 75 / (320 x 5)
c. 50 / (630 x 5)
d. 75 / (320 + 5)
e. 245 / (320 x 5)

Key: True: e 245 / (320 x 5)
In a prospective study of the relationship between oral contraceptive use and the subsequent risk of developing endometrial cancer, a cohort of 1000 women were followed for 5 years. The results were as follows:

A 245
B 75
C 50
D 630
A + C = 295 B + D = 705 n = 1000
5. What is the relative risk in this study?
a. [75 / (245 + 75)] / [50 / (50 + 630)]
b. [75 / (245 + 75)] / [630 / (50 + 630)]
c. [50 / (245 + 50)] / [630 / (75 + 630)]
d. [245 / (245 + 75)] / [50 / (50 + 630)]
e. Insufficient data

Key: True: d [245 / (245 + 75)] / [50 / (50 + 630)]

6. Among 10 women with cervical cancer, medical records confirm a past history of herpes simplex type II infection in eight. What is the relative risk of developing cervical cancer in women with a history of HSV type II infection?
a. 8/10
b. 10/8
c. 8/2
d. 2/10
e. 2/8

Key: True: c

7. In an outbreak of cholera in a village of 2,000 population, 20 cases have occurred and 5 died. Case fatality rate is:
a. 1%
b. .25%
c. 5%
d. 25%
e. .0025%

Key: True: d

Questions # 8-9.
The results of a study of the incidence of pulmonary tuberculosis in a village in India are given in the table below. All persons in the village are examined during two surveys made 2 years apart, and the number of new cases was used to determine the incidence rate.

Category of Household at First survey Number of Persons Number of New cases
With culture positive case 500 10
Without culture positive case 10,000 10

8. What is the incidence of new cases per 1000 person years in households that had a culture positive case during the first survey?
a. 0.02
b. 0.01
c. 1.0
d. 10
e. 20

Key: True: d
10 new cases = 10 cases/1000 persons years
500 persons x 2 years

9. What is the incidence of new cases per 1000 person years in households that did not have a culture positive case during the first survey?
a. 0.001
b. 0.1
c. 0.5
d. 1.0
e. 5.0

Key: True: c
10 new cases = 0.5 cases/1000 persons years
10,000 persons x 2 years

10. In a population of 1000, measles coverage is 60%, one child goes out of station and comes back with measles from whom 20 more children get measles. Secondary attack rate of measles is:
a. 0.65%
b. 5%
c. 6%
d. 6.5%
e. 7%

Key: True: b
 Total No. of children=1000
 No. of immunized =600
 No. of un-immunized=400
 Primary case=1
 Secondary attack rate=20/(400-1)=20/399 X100= 5%

11. A village has total of 100 under-five children. The coverage with measles vaccine in this age group is 60%. Following the occurrence of a measles case in a child after a visit outside, twenty- six children developed measles. The secondary attack rate of measles is:
 25%
a. 40%
b. 50%
c. 65%
d. 66%

Key: True: e
 Total No. of children=100
 No. of immunized =60
 No. of un-immunized=40
 Primary case=1
 Secondary attack rate=26/(40-1)=26/39 X100= 66%

12. If an epidemiologist while investigating an epidemic makes a graph to plot distribution of cases of disease by the time of onset and gets a polymodal distribution curve. The most likely disease is:
a. Salmonellosis
b. Staphylococcal food poisoning
c. Measles
d. Typhoid
e. Hepatitis A

Key: True: c

13. 10 cases of food poisoning had been reported in hospital, 2 out of these developed mild gastrointestinal symptoms, 4 developed moderate dehydration but recovered and 2 succumbed to the disease. The characteristic of the organism of food poisoning that produces the severest form of the disease is:
a. Infectivity
b. Pathogenecity
c. Virulence
d. Communicability
e. Resistibility

Key: True: c

14. Public Policies in Pakistan aim at avoiding the underlying reasons for the development of environmental and atmospheric concentration of SO2 to protect the health of people. It’s an example of
a. Primordial
b. Primary
c. Secondary
d. Rehabilitation
e. Screening


Key: True: a

15. The number of deaths due to diarrhoea, total cases of measles, total number of accidents and the total number of drug addicts were to be reported by a researcher. The best title given to all of this data would be:
a. Mortality data
b. Morbidity data
c. Case fatality rate
d. Addiction rate
e. Health related data

Key: True: e

16. When total number of deaths due to measles is presented in relation to the total cases of measles, it is best labeled as:
a. Cause specific death rate
b. Incidence rate
c. Prevalence rate
d. Case fatality rate
e. Proportional mortality

Key: True: d

17. Japanese have a higher rate of stomach cancer and a low rate for colon carcinoma than the U.S. However third generation descendents of Japanese immigrants to U.S have rates of stomach & colon cancer like that of U.S. This particular characteristic supports effects of:
a. Environment
b. Genetics
c. Mutation
d. Accidents
e. Misinterpretation

Key: True: a

18. Influenza pandemic occurs after every 7 – 10 years. This kind of disease distribution in time is known as:
a. Secular trend
b. Short time fluctuation
c. Cyclical trend
d. Seasonal trend
e. Endemicity

Key: True: c

19. If the age incidences curve of leukemia shows two peaks it is suggestive of bimodality. Bimodality usually signifies:
a. Non homogeneity
b. Cluster sampling
c. Large number of observations
d. Accuracy
e. Short duration of disease

Key: True: a

20. A doctor is required to study the incidence of silicosis in a stone cutting industry, which study design should he choose:
a. Longitudinal
b. Cross-sectional
c. Ecological surveys
d. Case reports
e. Case series report

Key: True: a

21. The health statistics department revealed that the sale of anti-Asthma drugs was more in those countries where Asthma deaths were more. This association may prove wrong when the individual based study designs are conducted. This association is an example of:
a. Ecological fallacy
b. Berkesonian bias
c. Indirect association
d. Temporal association
e. Specific association

Key: True: a

22. A researcher wanted to study the time sequence to prove the concept of causativity, which design of study should be preferred by the researcher:
a. Longitudinal
b. Cross-sectional
c. Case report
d. Case series report
e. Quasi experimental

Key: True: a

23. Smoking leads to esophageal carcinoma. Coffee intake has its effect on smoking and also esophageal carcinoma. This factor can distort the results of the study which intends to prove an association between smoking and esophageal cancer. This effect of this factor is known as:
a. Confounding
b. Multiple causation
c. One to one relationship
d. Dose response relation
e. Strength of association

Key: True: a

24. The health authorities are launching a smoking cessation program by designing different activities for the smokers. These are very expensive but still useful as a large proportion of lung cancer will be eliminated if smoking is stopped. This proportion of lung cancer can be indicated by:
a. Relative risk
b. Prevalence
c. Attributable risk
d. Attributable fraction
e. Incidence density

Key: True: d

25. A researcher was studying maternal mortality in Rawalpindi District. He observed more deaths in women who were brought to hospital and without taking other factors into account concluded that hospital managed cases have more mortality as compared to home deliveries. This is an example of:
a. Indirect association
b. Relative risk
c. Spurious association
d. Attributable risk
e. Causal association

Key: True: c

26. Early diagnosis & prompt treatment is focused on:
a. Disease identification
b. Host factors
c. Environmental factors
d. Restoration of ability
e. Behaviour modification

Key: True: a

27. An expert in the field of public health is required to estimate the magnitude of a health problem. Which rate would he calculate for this?
a. Incidence
b. Prevalence
c. Case fatality
d. Proportionate mortality
e. Cause specific mortality

Key: True: b

28. When the number of educated females is expressed as a percentage of total females present in a village. It is known as:
a. Proportion
b. Rate
c. Ratio
d. Frequency
e. Cumulative frequency

Key: True: a

29. The trend in mortality from tuberculosis in England showed a steady fall in years 1855 – 1965 but thereafter a gradual rise in the incidence of this disease was reported. This type of time trend or fluctuation in disease occurrence is termed as:
a. Epidemic trend
b. Cyclical trend
c. Seasonal trend
d. Secular trend
e. Pandemic trend

Key: True: d

30. In the mid nineteenth century, an epidemiologist suggested that cholera was caused by drinking water in which an invisible agent is present. This type of association gives:
a. Specificity
b. Temporal sequence
c. Biological plausibility
d. Consistency
e. Gradient

Key: True: c

31. The incidence of pollen allergy at Faisalabad is 10 cases per thousand populations. The mean duration of illness is 3 months from February to April. The prevalence of pollen allergy at Faisalabad is:
a. 10
b. 20
c. 30
d. 40
e. 50

Key: True: c

32. When a new treatment is developed that delays deaths but does not produce
recovery from a chronic disease, which of the following will occur.
a. Prevalence of the disease will decrease
b. Incidence of the disease will increase
c. Prevalence of the disease will increase
d. Incidence of the disease will decrease
e. Incidence & prevalence of the disease will decrease

Key: True: c

33. If the number of deaths from tuberculosis is expressed in relation to the total mid year population, it is:
a. Case fatality rate
b. Age specific death rate
c. Proportionate mortality rate
d. Crude death rate
e. Cause specific death rate

Key: True: e

34.
Present Absent

A 200

B 100


C 100
D 200
A + C = 300 B + D = 300 n = 600
In a cohort study concerning the relationship between the use of exogenous
estrogens and the subsequent risk of breast cancer, a sample of 1000 pre- menopausal women were followed for 8 years. The results are presented in the table above. The absolute risk / incidence of blood cancer among women receiving estrogen therapy is:
a. 0.6
b. 0.2
c. 0.3
d. 0.4
e. 0.8

Key: True: a

35. The proportion of the disease in a population that would be eliminated if the risk factor is eliminated is determined by:
a. Relative risk
b. Absolute risk
c. Attributable fraction
d. Odds ratio
e. Exposure rate

Key: True: c

36. A 39-year-old man who presents with a mild sore throat, fever, malaise, and headache is treated with penicillin for presumed streptococcal infection. He returns after week with hypotension, fever, rash, and abdominal pain. He responds favorably to chloramphenicol, after a diagnosis of Rocky Mountain spotted fever is made. Which option explains the given example?
a. Case series report
b. Case-control study
c. Clinical trial
d. Cohort study
e. Case report

Key: True: e

37. A total of 3500 patients with thyroid cancer are identified and surveyed by patient interviews regarding past exposure to radiation. Which options explains the given example?
a. Case series report
b. Case-control study
c. Clinical trial
d. Cohort study
e. Case report

Key: True: a

38. A total of 10,000 Vietnam veterans, half of whom are known by combat records to have been in areas where Agent Orange was used and half of whom are known to have been in areas where no Agent Orange was used, are asked to give a history of cancer since discharge. Which option explains the given example?
a. Case series report
b. Case-control study
c. Clinical trial
d. Cohort study
e. Case report

Key: True: d

39. Patients admitted for carcinoma of the stomach are age and sex-matched, with
smoking history to assess the possible association. Which option explains the given example?
a. Case series report
b. Case-control study
c. Clinical trial
d. Cohort study
e. Case report

Key: True: b

40. California highway patrol statistics revealed that more accidents occurred to blue cars than to cars of any other colour. The inference that, while driving a blue car, one is at higher risk of accident than while driving a car of another colour is:
a. Correct
b. Incorrect, because the comparison is not based on rates
c. Incorrect, because no control or comparison group is used
d. Incorrect, because no test of statistical significance has been made
e. Incorrect, because prevalence is used instead of incidence

Key: True: b

41. In a study of 500 cases of a disease and 500 controls, the suspected etiological factor is found in 400 of the cases and 100 of the controls. The absolute risk (incidence) of disease in persons with the factor is:
a. 80%
b. 40%
c. 16%
d. 20%
e. Cannot be computed from data given

Key: True: e

42. In 1945, 1,000 women were identified who worked in a factory painting radium dials on watches. The incidence of bone cancer in these women up to 1975 was compared to that of 1,000 women who worked as telephone operators in 1945. Twenty of the radium dial workers and four of the telephone operators developed bone cancer between 1945 and 1975. The relative risk of developing bone cancer for radium dial workers is:
a. 2
b. 4
c. 5
d. 8
e. cannot be computed from the data given

Key: True: c

43. Prophylactic administration of vitamin K in breast fed babies is an example of:
a. Health Promotion
b. Treatment
c. Specific protection
d. Rehabilitation
e. Primordial prevention

Key: True: c


44. In an epidemiological study the incidence of disease in females is more than that of males but the prevalence is equal in both. It indicates:
a. Case fatality is more in female
b. Mortality in male is higher
c. Disease is of less duration in males
d. Females harbour disease for longer duration
e. Males harbour disease for longer duration

Key: True: a

45. Bhopal gas tragedy is an example of:
a. Slow epidemic
b. Continuous epidemic
c. Point source epidemic
d. Propagated epidemic
e. An accident which did not warrant an emergency

Key: True: c

46. Residents of three villages with three different types of water supply were asked to participate in a study to identify cholera carriers because several cholera deaths had occurred in the recent past. Virtually everyone was present at the time of examination. The proportion of carriers in each village was computed and compared. This study is a:
a. Cross-sectional study
b. Case-control study
c. Concurrent cohort study
d. Non-concurrent cohort study
e. Retrospective cohort study

Key: True: a

47. In a village of 1 lakh population, among 20,000 exposed to smoking, 200 developed cancer, and among 40,000people unexposed, 40 developed cancer. The relative risk of smoking in the development of cancer is:
a. 20
b. 10
c. 5
d. 15
e. 25

Key: True: b

48. In a population of 1000, measles coverage is 60%, one child goes out of station and comes back with measles from whom 26 more children get the measles. The secondary attack rate is:
a. 6.5
b. 65
c. 7.5
d. 0.65
e. 7.0

Key: True: a

49. To compare the death rate of India with the death rate of Pakistan, the most appropriate measure is a comparison between:
a. Age specific mortality rates
b. Crude death rates
c. Maternal mortality rates
d. Standardized mortality rates
e. Life expectancy

Key: True: d

50. About 2500 deaths were reported in road side accidents
during the year 2006 in Pakistan. If the total number of deaths due to accidents is expressed against the mid year population of Pakistan in year 2006 this will give:
a. Crude death rate
b. Age specific death rate
c. Cause specific death rate
d. Case fatality rate
e. Proportional mortality rate

Key: True: c

51. In a universe comprising of 1500 children less than 5 years of age, 75 children with severe malnutrition were found. If 75 new cases of severe malnutrition were registered over a period of one year, the incidence rate for severe malnutrition during the same year is:
a. 50 / 1000
b. 53 / 1000
c. 55 / 1000
d. 60 / 1000
e. 63 / 1000

Key: True: b

52. Every year during the winter season the hospital admissions are more for pneumonia cases. This year also about 358 children with pneumonia were admitted in the Pediatric department of POFHospital between the months of Jan – Mar 2007. This increased frequency of respiratory infections during winter months is an example of:
a. Epidemic trend
b. Cyclical trend
c. Seasonal trend
d. Secular trend
e. Pandemic trend

Key: True: c


53. Prevalence measures the burden of disease in a population inclusive of old & new cases. Prevalence of a disease can be obtained from:
a. Quasi – experimental study
b. Cross – sectional study
c. Case – control study
d. Cohort study
e. Intervention study

Key: True: b

54. A 55 years old hypertensive patient was admitted in the Medical Ward with cerebral stroke. After treatment he recovered but was unable to move his right lower limb. He was advised physiotherapy. This type of assistance is:
a. Health promotion
b. Specific protection
c. Prompt treatment
d. Disability limitation
e. Rehabilitation

Key: True: e

55. According to a study conducted by WHO the incidence of polio in Sindh province having a total population of 20 million was 1 during the year 2007, which type of study was this:
a. Case report
b. Cross sectional
c. Case control
d. Cohort
e. Ecological

Key: True: d

56. An epidemiologist is assigned to conduct a study on 5000 people having hyperlipidemia and those having normal lipid profile. He has to keep track of all the participants to observe the development of stroke in these patients to confirm that hyperlipidemia increases the risk of stroke. This study is:
a. Retrospective cohort study
b. Retrospective study
c. Prospective study
d. Cross – sectional study
e. Case – series

Key: True: c

57. To compare the death rate of Nepal with the death rate of Pakistan, the most appropriate measure is a comparison between:
a. Age specific mortality rates
b. Crude death rates
c. Maternal mortality rates
d. Standardized mortality rates
e. Life expectancy

Key: True: d

58. A 40 years old man of 75 kg came to a physician for his routine checkup. His serum cholesterol was found to be 230 mg/dL and he was diagnosed as hypertensive. The risk factor of this particular condition is classified as:
a. Physical
b. Chemical
c. Biological
d. Nutritive
e. Mechanical

Key: True: b

59. Acute hemorrhagic conjunctivitis affected a large proportion of population over a wide geographic area in 1971 and 1981. This spread of disease is:
a. Epidemic
b. Sporadic
c. Pandemic
d. Endemic
e. Opportunistic

Key: True: c

60. A patient came in emergency with signs of dehydration and severe diarrhea. An Intra venous infusion was given to correct electrolytes and fluid levels. He was discharged after 2 days. About 2 months later the patient came back with signs of jaundice and Hepatitis B surface antigen was positive. He did not give history of any event which could have lead to this disease. This hepatitis infection may be labeled as:
a. Sub clinical
b. Idiopathic
c. Opportunistic
d. Cross infection
e. Iatrogenic

Key: True: e

61. A cross-sectional study was conducted in the year 2006 to measure the period prevalence of smokers among 105 students. Out of them 5 were already smokers and 15 started during 2006, period prevalence of 2006 is:
a. 22%
b. 19%
c. 15%
d. 11%
e. 10%

Key: True: b

62. In a village of population 10,000, 250 cases of Hepatitis B were reported in the month of July. The point prevalence of Hepatitis B per thousand populations is:
a. 20
b. 25
c. 30
d. 50
e. 100

Key: True: b

63. A household survey of 10 families was conducted by students of 4th year MBBS. In the data they collected, the ages of heads of families were: 32, 34, 35, 36, 36, 42, 44, 46, 48, 52. The mean age of heads of families is
a. 36
b. 38.5
c. 40
d. 40.5
e. 42

Key: True: d

64. A woman brings her child to the hospital for mongolism. The possible agent of the disease that comes in your mind is?
a. Bacteria
b. Virus
c. Nutritional factor
d. Hormonal factor
e. Chromosomal factor

Key: True: e

65. A child of three years comes with complaints of night blindness. On examination conjunctiva is dry and corneal haziness is also seen. There is no history of any other disease or injury. The likely agent type is:
a. Physical
b. Chemical
c. Nutritional
d. Hormonal
e. Immunological

Key: True: c

66. A man brought his child with complaints of fever, diarrhea and abdominal pain. He gave history of living in an unhygienic small house around a factory area where his son had many friends. He had three more children who also had same complaints off and on. Which environment is likely to have resulted in this condition?
a. Physical
b. Chemical
c. Social
d. Psychological
e. Occupational

Key: True: a

67. A new drug was introduced in some of patients to assess its usefulness compared with the old one. Neither patients nor clinicians who evaluated patients for effect under consideration in this clinical trial knew individual treatment assignments. This method of assignment is known as:
a. Single blinding
b. Double blinding
c. Triple blinding
d. Randomization
e. Stratification

Key: True: b

68. 10 cases of food poisoning had been reported in a hospital, 2 out of these developed mild gastrointestinal symptoms, 4 developed moderate dehydration but recovered and 2 succumbed to the disease. The characteristic of the organism of food poisoning that produces the severest form of the disease is:
a. Infectivity
b. Pathogenicity
c. Virulence
d. Communicability
e. Resistibility

Key: True: c

69. The trend in mortality from tuberculosis in England showed a steady fall in years 1855 – 1965 but thereafter a gradual rise in the incidence of this disease was reported. This type of time trend or fluctuation in disease occurrence is termed as:
a. Epidemic trend
b. Cyclical trend
c. Seasonal trend
d. Secular trend
e. Pandemic trend

Key: True: d

70. An outbreak of brucellosis in cattle is reported, threatening the health of human population. This outbreak is:
a. Epizootic
b. Epornithic
c. Enzootic
d. Exotic
e. Epidemic

Key: True: a

71. A survey report in 1960 concluded that there was an increase in asthma deaths with the increased use of pressurized aerosol bronchodilators; although the deaths were more because of the severity of disease. This association is:
a. Spurious
b. Temporal
c. Indirect
d. Consistency
e. Coherence

Key: True: a

72. In a coal mine the expected deaths of coal worker were 7 while the deaths that really occurred were 9. The standardized mortality ratio for coal workers is:
a. 100
b. 109
c. 115
d. 129
e. 130

Key: True: d

73. At Lahore Grammar School a student of class II developed mumps. He was isolated from other children till swelling subsided and his brother of class IV who looked apparently healthy was also advised to be away from school for about a fortnight. His brother’s type of carrier state is most likely to be:
a. Incubatory
b. Healthy
c. Convalescent
d. Temporary
e. Chronic

Key: True: a

74. In a colony located near an industrial area 50 people died due to asphyxia and many developed difficulty in breathing and were hospitalized within 24 hours. The cause was the leakage of carbon monoxide from a near by chemical plant. The distribution of cases in time is suggestive of:
a. Propagated epidemic
b. Slow epidemic
c. Common source – single exposure
d. Common source – continuous exposure
e. Pandemic

Key: True: c

75. Cement industry is suspected for more deaths among its workers. So the industrialist gets worried and wants to assess whether more deaths are likely in these workers or not. The measure that predicts the mortality in this industrial group is:
a. Age specific death rate
b. Standardized mortality ratio
c. Cause specific death rate
d. Proportionate mortality
e. Case fatality rate

Key: True: b

76. The annual report of POF Hospital for the year 2006 shows 200 cases of Myocardial Infarction, 35 cases of Cholecystitis, 105 cases of Pneumonia and 350 cases of Acute Gastroenteritis. The result of this report cannot be generalized on the total population of Faisalabad on account of:
a. Confounding bias
b. Memory bias
c. Selection bias
d. Berkesonian bias
e. Interviewer’s bias

Key: True: d

77. Increased number of Malaria cases was reported in the time intervals between August to October and March to April. There are 2 different periods in a year, where increased malaria transmission is reported. Such an occurrence of malaria cases in time will give a distribution which is:
a. Unimodal
b. Sporadic
c. Bimodal
d. Endemic
e. Multimodal

Key: True: c

78. .In the medical OPD of teaching hospital of a Medical College, diastolic blood pressures of 10 patients were as follows:
80 , 75 , 81 , 79 , 71 , 95 , 75 , 77 , 84 & 90. The mean of this data is:
a. 80
b. 81
c. 82
d. 83
e. 84

Key: True: b

80. In a poor community, there is high prevalence of acute diarrhea cases. The best method for preventing this health problem in the long run is:
a. Anti diarrheal drugs.
b. Immunization against cholera and typhoid
c. Provision of sanitary latrine.
d. Use of boiled water.
e. Living in fly proof zone.

Key: True: c


81. In a sample of 49 individuals, the mean total leukocyte count is found to be 7600 cells /mm3, If total leukocyte count follows a normal distribution curve, the 50 % of the individuals will have which of the following values:
a. Between 6200 and 9000
b. Between 7400 and 7800
c. Below 6200 or Above 9000
d. Below 7600
e. Above 9000

Key True: d

82. In a sample of 49 individuals, the mean total leukocyte count is found to be 7600
cells /mm3 and standard deviation of 1400 /mm3, a randomly selected individual will have total leukocyte count lower than 4800 cell /mm3
a. 1 % of the Time
b. 2.5 % of the Time
c. 5 % of the Time
d. 10 % of the Time
e. 16.5 % of the Time

Key True: b

83. Higher crude annual mortality rate in a developing country as compared to a developed country is mostly due to one of the following reasons:
a. An incorrect record keeping
b. A younger age distribution
c. An inaccurate census of the population.
d. More stressful life style
e. Greater exposure to occupational hazards.

Key True: b

84. Birth rates of a population of infants at 40 weeks gestational age are approximately normally distributed, with a mean of 3000 grams. Roughly 68% of such infants weigh between 2500 and 3500 at birth. If a sample of 100 infants was studied, the standard error would be
a. 50
b. 100
c. 250
d. 500
e. None of the above

Key: True: a

85. In 1993 Burkina Faso had Grossreproductive rate of 3.5 while United Kingdom was only 0 .86 that means if 1993 Fertility levels were to continue, which one of the following options will be correct.
a. The Net Reproductive Rate of Burkina Faso would definitely be more than 3.5
b. In United Kingdom, a woman would produce more than one daughter on average during her life time.
c. In Burkina Faso, a woman would produce 3.5 daughters on average through her life time
d. The Net Reproductive Rate of UK will be more than one.
e. The Net Reproductive Rate of Burkina Faso would be equal to Gross Reproductive Rate of the country

Key: True: c

86. The estimate of the average number of additional years a person could expect to live if the age specific death rates for a given year prevailfor the rest of his life, is best expressed by:
a. Survival index
b. Probability of dying
c. Life expectancy
d. Crude death rate
e. Age specific death rate

Key: True: c

87. A patient who has come from India, reports to a health facility with generalized
aches and pain and rash on the body excluding palms and soles. The most likely
diagnosis is:
a. Scarlet fever
b. Trypanosomniasis
c. Malaria
d. Dengue
e. Yellow Fever

Key: True: d

88. In a Medical journal report, the observed mortality of smokers and nonsmokers for laryngeal squamous cell carcinoma was reported to be significant at p < 0.05. Such a statement means that a. The investigator is rejecting the null hypothesis even though the results could have occurred purely by chance a maximum of 5 times out of 100. b. There is a difference between the mortality rates of smokers and nonsmokers 5% of the time c. The null hypothesis claims that there is a difference between the mortality rates of smokers and nonsmokers. d. A causal relationship between smoking and mortality may be established through this study e. There is insufficient data, as the total number of smokers and nonsmokers were not given.

Key: True: a

89. In study carried out in the hospital ward, every 10th admitted patient was included in the
sample, which sampling procedure is this: a. Random sampling b. Stratified sampling c. Quota sampling d. Convenient sampling e. Systematic sampling

Key: True: e

90. Three groups of subjects were followed over the course of five years to compare treatments for sideroblastic anemia. The most appropriate statistical analysis to determine the quantitative serologic differences resulting from these treatments would be a(n) a. Regression analysis b. F test (ANOVA) c. Correlation analysis d. Chi-square test e. T test

Key: True: b

91. Breast Cancer Present Absent A 300 B 200 C 100 D 400 A + C = 400 B + D = 600 n = 1000 In a cohort study concerning the relationship between the use of exogenous estrogens and the subsequent risk of breast cancer, a sample of 1000 premenopausal women were followed for 8 years. The results are presented in the table above. The absolute risk of blood cancer among women receiving estrogen therapy is a. 0.2 b. 0.3 c. 0.4 d. 0.6 e. 0.8

Key: True: d

93. In a cohort study concerning the relationship between the use of exogenous estrogens and the subsequent risk of breast cancer, a sample of 1000 premenopausal women were followed for 8 years. The results are presented in the table above. The absolute risk of breast cancer among women who did not receive estrogen therapy is a. 0.05 b. 0.2 c. 0.4 d. 0.6 e. 0.8

Key: True: b

94. In a cohort study concerning the relationship between the use of exogenous estrogens and the subsequent risk of breast cancer, a sample of 1000 premenopausal women were followed for 8 years. The results are presented in the table above. The relative risk associated with estrogen therapy in this study is a. 0.25 b. 0.33 c. 0.5 d. 2 e. 3

Key: True: e

95. Following a large group of cigarette smokers for a period of 10 years to determine the occurrence of chronic obstructive pulmonary disease (COPD), coronary heart disease, and various forms of lung cancer would be an example of a. Randomized clinical trial b. Cross-sectional study c. Prevalence study d. Cohort study e. Case-control study

Key: True: d

97. A nutritional research team followed serum levels of vitamin B12 and folic acid in 125 children for five years to determine the association between cyanocobalamin deficiency and the subsequent risk of developing megaloblastic anemia. The results were as follows: VITAMIN B12 LEVELS Mean 262 pg/mL Median 228 pg/mL Mode 196 pg/mL From the data, it can be concluded that this distribution is a. Normal b. Positively skewed c. Negatively skewed d. Skewed toward the left e. Unable to be identified

Key: True: b

98. If, in one of the groups of premature infants, the maximum value for hexosaminidase A was substituted with a much higher value, which of the given values remains unchanged: a. Variance b. Range c. Standard deviation d. Median e. Mean

Key: True: d

99. In a cohort study involving the relationship between HIV status and the subsequent risk of developing pneumocystis carinii pneumonia, 50 HIV-positive volunteers were followed for 6 months: 100 for 1 year, 100 for 3 years, and 200 for 5 years. The number of person-years of observation in this study was a. 9.5 b. 1425 c. Unable to be determined for different periods d. Unable to be determined without a mortality rate e. Unable to be determined without an incidence rate

Key: True: b

100. The smoking history of pregnant women is taken in the antenatal period and correlated with the birth weight at the time of delivery. To find an association between them would be an example of: a. Clinical trial b. Nested cohort study c. Retrospective study d. Prospective study e. Cross sectional study

Key: True: d

101. In a study of 500 cases of a disease and 500 controls, the suspected etiological factor is found in 400 of the cases and 100 of the controls. The absolute risk (incidence) of disease in persons with the factor is: a. 80% b. 40% c. 16% d. 20% e. Cannot be computed from data given

Key: True:

102. Prophylactic administration of vitamin K in breast fed babies is an example of: a. Health Promotion b. Treatment c. Specific protection d. Rehabilitation e. Primordial

Key: True: c

103. In a bulk of hundred children out of whom 28 are immunized 2 of them get measles simultaneously. Subsequently14 get measles. Assuming the efficacy of the vaccine to be 100%, what is the secondary attack rate? a. 5% b. 10% c. 20% d. 21.5% e. 19.4%

Key: True: c

104. A village has a total of 100 under-five children. The coverage with measles vaccine in this age group is 60% (assuming the efficacy of vaccine to be 100%). Following the occurrence of a measles case in a child after a visit outside, twenty- six children developed measles. The secondary attack rate of measles is: a. 25% b. 40% c. 50% d. 65% e. 66%

Key: True: e

105. In an epidemiological study the incidence of disease in females is more than that of males but the prevalence is equal in both. It indicates: a. Case fatality is more in female b. Mortality in male is higher c. Disease is of less duration in males d. Females harbour disease for longer duration e. Males harbour disease for longer duration

Key: True: a

106. Which one of the following is the Odds ratio, calculated from the given data? Diseased Un-diseased Positive 30 20 Negative 20 30 a. 0.44 b. 1.5 c. 0.8 d. 2.25 e. 2.00

Key: True: d

107. A total of 300 newly diagnosed patients with laryngeal cancer are allocated to treatment with either surgical excision alone or surgical excision plus radiation treatment. What is the study design? a. Case series report b. Case-control study c. Clinical trial d. Cohort study e. Case report

Key: True: c

108. An analysis of the race of patients who visit an emergency room reveals that 40% are white, 25% are black, 20% are Native American, and 15% are Asian. These data would best be depicted graphically with a a. Venn diagram b. Cumulative frequency graph c. Normal curve d. Histogram e. Pie chart

Key: True: e

109. A study was conducted in America to find out the proportion of blacks and white Americans in California. This variable chosen is: a. Nominal b. Ordinal c. Continuous d. Discreet numerical e. Dichotomous

Key: True: e

110. A public health physician wants to study the load of hypertension in Rawalpindi district to establish special screening & treatment services in the mentioned area. Which design is more useful for this? a. Cross sectional b. Case series c. Cohort d. Case control e. Experimental

Key: True: a

111. Japan has a high rate of stomach carcinoma and a low rate of colon carcinoma than the U.S. Which study would you suggest to prove or support the environmental effect on the incidence of these cancers? a. Migrant studies b. Case control c. Incidence d. Case reports e. Mortality survey

Key: True: a

112. To give the relevant importance to hypertension control in a health service a researcher wants to study the prevalence of hypertension. He chose a cohort study. The design to assess prevalence is? a. Inappropriate b. Suitable c. Quick d. Feasible e. Expensive

Key: True: a

113. A researcher wants to study natural history of silicosis in a population of industrial workers. Which design is most useful? a. Cross sectional b. Case report c. Case control d. Incidence e. Ecological survey

Key: True: d

114. If a researcher wants to study precedence relationship between the exposure and effect, which design should he prefer? a. Descriptive survey b. Ecological survey c. Case series d. Cross sectional e. Cohort

Key: True: e

30. Smokers have risk of lung cancer four times more than non smokers. If smoking indicates causal association this characteristic gives: a. Specificity b. Strength of association c. Coherence d. Consistency e. Temporal sequence

Key: b

31. The incidence of gonorrhoea is continuously increasing in a particular locality. An investigator reveals that mostly sex workers are living there. This epidemic may be classified as: a. Common source single exposure b. Common source continuous exposure c. Propagated epidemic d. Slow epidemic e. modern epidemic

key: b

32. A public health physician wants to study the load of hypertension in Rawalpindi district to establish special screening & treatment services in the mentioned area. Which design is more useful for this? f. Cross sectional g. Case series h. Cohort i. Case control j. Experimental

Key: a

33. In a prospective study of the relationship between oral contraceptive use and the subsequent risk of developing heart disease, a cohort of 1000 women were followed for 5 years. The results were as follows: Present Absent A 245 B 75 C 50 D 630 A + C = 295 B + D = 705 n = 1000 What is the incidence rate (absolute risk) of endometrial cancer among those who didn’t use oral contraceptives? f. 630 / (50 + 630) g. 75 / (245 + 75) h. 50 / (50 + 630) i. 245 / (245 + 75) j. 680/(320+680)

Key: True: c 50/(50 + 630)

34. 10 cases of food poisoning had been reported in hospital, 2 out of these developed mild gastrointestinal symptoms, 4 developed moderate dehydration but recovered and 2 succumbed to the disease. The characteristic of the organism of food poisoning that produces the severest form of the disease is: f. Infectivity g. Pathogenicity h. Virulence i. Communicability j. Resistibility
Key: c

1. Different students have proved that prevalence of Alzheimer’s disease increase with increasing population ages. Other aspects of descriptive epidemiology proves low incidence in Native Americans. Which contributing factor is more common in the above disease based on the scenario: a. Genetic b. Geographic distribution c. Diet d. Health coverage e. Ethinicity 2. Incidence of prostate carcinoma is much lower in Japan than US. First generation of migrants from Japan to US also have relatively low incidence rates but the rates increase successively in subsequent generation this supports effect of : a. Temporal variation b. Genetics c. Environment d. Nutrition e. Stress 65. The incidence of gonorrhoea is continuously increasing in a particular locality. An investigator reveals that in that area mostly sex workers are living. This epidemic may be classified as: f. Common source single exposure g. Common source continuous exposure h. Propagated epidemic i. Slow epidemic j. modern epidemic

key: b

66. In Rawalpindi general hospital during the month of December, a total of 10 patients were admitted with diagnosis of meurngococcal meningitis. The total inpatients in that month were 800. What is the incidence rate of meningocacal meningitis for the month of December? a. 11.5 / 1000 b. 12.5 / 1000 c. 13.0 / 1000 d. 9.0 / 1000 e. 10.5 / 1000

Key: b