Epidemiology Practice Questions

Q: Which one of the following statements is NOT true for taking a decision on screening for disease?

Proportion of false negatives is high. ***Proportion of false negatives is high*** - A **high proportion of false negatives** means that many individuals with the disease are missed by the screening test. - This is **absolutely undesirable** for screening and directly contradicts the fundamental principle that screening tests should have **high sensitivity**. - This statement is clearly NOT true as a criterion for making screening decisions. *Sensitivity and specificity are high* - **High sensitivity** means the test correctly identifies most people who have the disease, minimizing false negatives. - **High specificity** means the test correctly identifies most people who do not have the disease, minimizing false positives. - Both are desirable characteristics according to Wilson-Jungner screening criteria. *Disease prevalence should be high* - This statement is **oversimplified and not strictly accurate** according to Wilson-Jungner criteria. - The actual criterion is: **"The condition should be an important health problem"** - based on disease burden, severity, and consequences, NOT necessarily high prevalence. - Many successful screening programs target **low prevalence diseases** (e.g., phenylketonuria in newborns, congenital hypothyroidism). - What matters is the **positive predictive value (PPV)** and cost-effectiveness, which are influenced by prevalence but don't require "high" prevalence. *Disease is lethal* - The Wilson-Jungner criterion states the disease should have **"serious consequences if left untreated"** - this includes but is not limited to lethality. - Screening is justified for diseases causing **significant morbidity or mortality** where early detection improves outcomes. - The disease should be sufficiently serious to warrant the costs and potential harms of screening.

Q: The sequence of events leading to disability and handicap is:

Disease → Impairment→Disability→Handicap. ***Disease → Impairment→Disability→Handicap*** - This sequence follows the **WHO International Classification of Impairments, Disabilities, and Handicaps (ICIDH, 1980)** model, which correctly illustrates the progression from a health condition to its societal consequences. - A **disease** or health condition leads to **impairment** (loss or abnormality of body structure/function), which then restricts activities (**disability**), and ultimately impacts social roles (**handicap**). *Disease → Disability→Impairment→Handicap* - This order is incorrect because **impairment** (a problem in body function or structure) logically precedes **disability** (a difficulty executing tasks). - **Disability** arises from the *functional limitation* caused by impairment, not the other way around. *Disease → Disability→Handicap→Impairment* - This sequence is incorrect as **impairment** is the initial consequence of disease on a functional level, occurring before **disability** and **handicap**. - **Handicap** represents the societal and environmental disadvantage, which is the final stage in this classic WHO model. *Disease → Handicap→Impairment→Disability* - This order is incorrect because **handicap**, which refers to a social disadvantage, is the last step in the disablement process, following impairment and disability. - **Impairment** is a direct result of the disease, and **disability** follows from that impairment.

Q: Physical Quality of life consolidates which of the following indicators? 1. Infant Mortality Rate 2. Life expectancy at birth 3. Literacy 4. Per capita income 5. Mean years of schooling 6. Life expectancy at age one Select the correct answer using the code given below:

1, 3 and 6. ***1, 3 and 6*** - The **Physical Quality of Life Index (PQLI)** comprises **infant mortality rate**, **life expectancy at age one**, and **literacy rate**. - These indicators were selected to reflect basic human needs and well-being, independent of purely economic measures. *1, 2 and 3* - While **infant mortality rate** and **literacy** are part of PQLI, **life expectancy at birth** is not one of its three core components. - PQLI specifically uses **life expectancy at age one** to avoid the significant influence of high infant mortality on overall life expectancy at birth. *2, 3 and 6* - **Life expectancy at age one** and **literacy** are included in PQLI, but **life expectancy at birth** is not. - The PQLI's design intentionally focuses on outcomes after the critical first year of life. *1, 4 and 5* - **Infant mortality rate** is a PQLI component, but **per capita income** and **mean years of schooling** are not. - **Per capita income** is an economic indicator and explicitly excluded from PQLI, while **mean years of schooling** is more commonly associated with the Human Development Index (HDI).

Q: Disability-adjusted life years (DALYs) include:

Both YLL and YLD. ***Both YLL and YLD*** - **DALYs (Disability-Adjusted Life Years)** are a measure of overall disease burden, expressed as the number of years lost due to ill-health, disability, or early death. - They are calculated as the sum of **Years of Life Lost (YLL)** due to premature mortality and **Years Lost due to Disability (YLD)** for people living with a health condition or its consequences. *Neither YLL nor YLD* - This statement is incorrect because DALYs are explicitly designed to integrate both premature mortality (YLL) and the impact of non-fatal health outcomes (YLD). - Excluding both components would render DALYs meaningless as a comprehensive health metric. *Years lost to disability (YLD)* - While **YLD** is a crucial component of DALYs, focusing solely on YLD would ignore the impact of premature mortality. - A healthy life lost due to early death is as significant as years living with a disability in assessing disease burden. *Years of lost life (YLL)* - While **YLL** is an essential component, considering only YLL would overlook the burden of morbidity and disability. - Many chronic diseases cause significant disability and reduced quality of life without necessarily leading to premature death, which YLD accounts for.

Q: Consider the following data for a country: What shall be the dependency ratio of this country?

54.1 %. ***54.1 %*** - The **dependency ratio** measures the proportion of dependents (children 0-14 and elderly 65+) to the working-age population (15-64). - Calculation: ((391,558,367 + 71,943,390) / 856,076,200) × 100 = (463,501,757 / 856,076,200) × 100 = **54.14%**. *42.4 %* - This value is significantly **lower** than the calculated dependency ratio of 54.1%. - Would indicate a much smaller **dependent population** relative to the working-age group. *66.2 %* - This percentage is **higher** than the mathematically correct dependency ratio calculation. - Would suggest a larger proportion of **dependents** than actually exists in the given data. *78.6 %* - This value is significantly **overestimated** compared to the calculated dependency ratio. - Such a high ratio would indicate an unrealistic proportion of **non-working population** to working-age adults.

Q: Which one of the following is NOT a function of Epidemiology?

Making a clinical diagnosis. ***Making a clinical diagnosis*** - **Epidemiology** focuses on **population-level health patterns** and determinants of disease, not individual patient diagnosis. - Making a **clinical diagnosis** is the role of a healthcare provider based on a patient's symptoms, physical examination, and diagnostic tests. *Searching for the causes and risk factors* - A primary function of epidemiology is to **identify potential causes** and **risk factors** for diseases within populations. - This involves investigating associations between **exposures** and **health outcomes**. *Identifying syndromes* - Epidemiologists help identify new or unrecognized **patterns of disease** presentation that may constitute a **syndrome**. - This involves observing **clusters of symptoms** or conditions in a population. *To study historically the rise and fall of disease in the population* - **Historical epidemiology** tracks changes in disease incidence, prevalence, and mortality over time. - This function helps understand disease trends and the **impact of public health interventions**.

Q: In a cohort of 500 women attending antenatal clinic, 70 % had ultrasonography (USG). This cohort was followed up at delivery. Of the women who had USG, 70 delivered low birth weight (LBW) babies; whereas of the women, who did not undergo USG, 50 delivered LBW babies. The incidence of LBW babies among women who had USG is:

20 %. ***20 %*** - Total women are 500, and 70% had USG, which equals 350 women. - Of these 350 women, 70 delivered **low birth weight (LBW)** babies. Therefore, the incidence is (70/350) * 100% = **20%**. *25 %* - This option would imply a higher number of LBW babies among those who had USG than the actual data. - It does not align with the calculation based on the given figures (70 LBW babies out of 350 women who had USG). *10 %* - This option represents a lower incidence and does not correspond to the calculation of (70/350) * 100%. - This value might be obtained if the total number of women with USG was incorrectly assumed to be 700. *15 %* - This option is incorrect as it does not match the calculated incidence of LBW babies among women who underwent USG. - This would mean only 52.5 LBW babies were born, which contradicts the information given that 70 delivered LBW babies.

Q: Poor hand hygiene of a mess worker in a university college mess led to Hepatitis A cases in the hostel inmates. What type of epidemic will this exposure present with? 1. Propagated 2. Common source-continuous exposure 3. Common source-point exposure Select the correct answer using the code given below:

2 only. ***2 only*** - A mess worker with **ongoing poor hand hygiene** represents a **continuous common source exposure**. The worker continues to handle food over days or weeks with persistent poor hygiene, leading to **repeated contamination** and cases occurring over an extended period rather than clustered around a single incubation period. This produces a plateau-like epidemic curve characteristic of continuous exposure. *1 only* - **Propagated epidemic** occurs through **person-to-person transmission** (e.g., measles, chickenpox), where each case can generate new cases, creating successive waves with progressively larger peaks. Hepatitis A from a food handler is a **common source outbreak**, not propagated, as cases trace back to contaminated food rather than spreading between inmates. *1 and 3* - Option 1 (propagated) is incorrect as explained above. Option 3 (**common source-point exposure**) would apply if there was a **single, brief contamination event** (e.g., one contaminated meal), resulting in cases appearing within one incubation period with a sharp peak. The scenario describes **persistent poor hygiene** suggesting ongoing contamination, not a single point event. *1 and 2* - Option 1 (propagated) is incorrect as this is a common source outbreak from contaminated food, not person-to-person transmission.

Q: Keeping biological determinants in perspective, consider the following statements: 1. Presence of a normal karyotype is the first requisite for human health 2. Genetic screening can play an important role in prevention of wide spectrum of diseases 3. If an individual is allowed to live in healthy relationship with the environment, the person's genetic potentialities can transform into phenotypic realities Which of the above statements is/are correct?

2 and 3 only. ***Correct: 2 and 3 only*** **Statement 2 - Genetic screening (CORRECT):** - Genetic screening is a powerful tool in preventive medicine - **Newborn screening** identifies conditions like PKU, congenital hypothyroidism, enabling early intervention - **Carrier screening** prevents diseases like thalassemia and sickle cell disease - **Predictive testing** (e.g., BRCA1/2) allows risk-based prevention strategies - Enables **primary and secondary prevention** across a wide spectrum of genetic conditions **Statement 3 - Gene-environment interaction (CORRECT):** - Fundamental principle of **genetics and public health** - An individual's genetic potential requires a **healthy environment** for optimal expression - **Phenotypic realities** emerge from the interplay between genotype and environmental factors - Supports the concept of **positive health** and health promotion - Underscores importance of favorable living conditions, nutrition, and social determinants **Statement 1 - Normal karyotype as first requisite (INCORRECT):** - This is **too absolute** and medically inaccurate - Many chromosomal variations compatible with healthy life (Turner syndrome, Klinefelter syndrome) - Severe diseases can occur despite **normal karyotype** (multifactorial diseases, acquired conditions) - Health is multifactorial - not determined by karyotype alone - Normal karyotype is favorable but not an absolute "first requisite" *Incorrect: 1 and 2 only* - Statement 1 is incorrect, invalidating this option *Incorrect: 1, 2 and 3* - Statements 2 and 3 are correct, but inclusion of incorrect statement 1 makes this option wrong *Incorrect: 1 and 3 only* - Statement 1 is incorrect, invalidating this option

Question 1

Standardized Mortality ratio is best explained by which one of the following statements?

Accepted Answer

Ratio of observed number of deaths to the expected number of deaths in a population

Answer

New spells of disease in a given period of time per 1000 population

Answer

Number of deaths in a given period of time per 1000 population

Answer

Percentage of deaths in women as compared to deaths in men

Question 2

Which one of the following statements is NOT true for taking a decision on screening for disease?

Accepted Answer

Proportion of false negatives is high

Answer

Sensitivity and specificity are high

Answer

Disease prevalence should be high

Answer

Disease is lethal

Question 3

The sequence of events leading to disability and handicap is:

Accepted Answer

Disease → Impairment→Disability→Handicap

Answer

Disease → Disability→Impairment→Handicap

Answer

Disease → Disability→Handicap→Impairment

Answer

Disease → Handicap→Impairment→Disability

Question 4

Physical Quality of life consolidates which of the following indicators?

1. Infant Mortality Rate
2. Life expectancy at birth
3. Literacy
4. Per capita income
5. Mean years of schooling
6. Life expectancy at age one

Select the correct answer using the code given below:

Accepted Answer

1, 3 and 6

Answer

1, 2 and 3

Answer

2, 3 and 6

Answer

1, 4 and 5

Question 5

Disability-adjusted life years (DALYs) include:

Accepted Answer

Both YLL and YLD

Answer

Neither YLL nor YLD

Answer

Years lost to disability (YLD)

Answer

Years of lost life (YLL)

Question 6

Consider the following data for a country: What shall be the dependency ratio of this country?

Accepted Answer

54.1 %

Answer

42.4 %

Answer

78.6 %

Answer

66.2 %

Question 7

Which one of the following is NOT a function of Epidemiology?

Accepted Answer

Making a clinical diagnosis

Answer

Searching for the causes and risk factors

Answer

Identifying syndromes

Answer

To study historically the rise and fall of disease in the population

Question 8

In a cohort of 500 women attending antenatal clinic, 70 % had ultrasonography (USG). This cohort was followed up at delivery. Of the women who had USG, 70 delivered low birth weight (LBW) babies; whereas of the women, who did not undergo USG, 50 delivered LBW babies. The incidence of LBW babies among women who had USG is:

Accepted Answer

20 %

Answer

25 %

Answer

10 %

Answer

15 %

Question 9

Poor hand hygiene of a mess worker in a university college mess led to Hepatitis A cases in the hostel inmates. What type of epidemic will this exposure present with?

1. Propagated
2. Common source-continuous exposure
3. Common source-point exposure

Select the correct answer using the code given below:

Accepted Answer

2 only

Answer

1 only

Answer

1 and 3

Answer

1 and 2

Question 10

Keeping biological determinants in perspective, consider the following statements:

1. Presence of a normal karyotype is the first requisite for human health

2. Genetic screening can play an important role in prevention of wide spectrum of diseases

3. If an individual is allowed to live in healthy relationship with the environment, the person's genetic potentialities can transform into phenotypic realities
Which of the above statements is/are correct?

Accepted Answer

2 and 3 only

Answer

1 and 2 only

Answer

1, 2 and 3

Answer

1 and 3 only

Epidemiology — MCQs

Epidemiology — MCQs

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