Community Medicine
10 questionsIn the context of a new onset of a morbid disease, how does the change in incidence affect the prevalence of the disease?
Calculate the relative risk for the given situation: Developed Malaria | Did Not Develop Malaria | Total Vaccinated 6 | 94 | 100 Non-vaccinated 12 | 88 | 100
A gym owner observes that individuals who drink iced tea during their workouts tend to lose more weight. What is the nature of this relationship?
A study was conducted in 3 communities (across 3 states) to measure the mean blood pressure in each community. Health workers were assigned to visit each house in the 3 communities. The mean blood pressure of each community was then compared. What is the study design called?
Which of the following is a technology-based surveillance system for tuberculosis (TB) in India?
Wasting in a child is assessed by which of the following measures?
For what population size is an urban Primary Health Centre (PHC) typically intended?
What were the goals for Maternal Mortality Rate (MMR) and Infant Mortality Rate (IMR) as per India's National Health Policy 2017 intermediate targets?
Which of the following is the vector responsible for transmitting Orientia tsutsugamushi?
What concentration of fluoride is typically associated with causing crippling fluorosis?
FMGE 2024 - Community Medicine FMGE Practice Questions and MCQs
Question 31: In the context of a new onset of a morbid disease, how does the change in incidence affect the prevalence of the disease?
- A. Prevalence is not related to incidence
- B. Incidence will increase, and prevalence will decrease
- C. Incidence and prevalence will increase (Correct Answer)
- D. Prevalence will increase with a decrease in the incidence
Explanation: ***Incidence and prevalence will increase*** - **Incidence** is the rate of new cases arising in a population; a "new onset" inherently implies that the occurrence of **new cases** is rising or starting. - Since **prevalence** is the total number of existing cases (P ≈ I × D, where D is duration), a rise in new cases (**incidence**) directly contributes to and increases the total existing burden of the disease. *Prevalence is not related to incidence* - This is incorrect because **incidence** (the inflow of new cases) is the primary determinant, along with duration and mortality/cure, of the overall total number of existing cases (**prevalence**). - Prevalence is mathematically linked to incidence; if incidence rises, prevalence typically rises, and if incidence approaches zero, prevalence will eventually fall (assuming cases are cleared). *Incidence will increase, and prevalence will decrease* - When **incidence** increases (more new cases), it leads to an increased rate of accumulation of cases, which consequently increases **prevalence**. - Prevalence only decreases despite increasing incidence if the removal rate (due to death or cure) drastically exceeds the rate of new cases, which is highly unlikely in a scenario described as a "new onset" morbid disease. *Prevalence will increase with a decrease in the incidence* - A decrease in **incidence** (fewer new cases) leads to a decrease in **prevalence** over time, assuming the duration of the disease remains stable. - Prevalence can increase with decreasing incidence only if the **duration** of the disease or survival time increases significantly (e.g., effective palliative treatment without cure), trapping existing cases in the prevalent pool.
Question 32: Calculate the relative risk for the given situation: Developed Malaria | Did Not Develop Malaria | Total Vaccinated 6 | 94 | 100 Non-vaccinated 12 | 88 | 100
- A. 1.5
- B. 2
- C. 1.7
- D. 0.5 (Correct Answer)
Explanation: ***Correct: 0.5*** **Relative Risk (RR)** is calculated as: RR = Risk in exposed group / Risk in unexposed group **Step-by-step calculation:** - Risk in **vaccinated group** = 6/100 = 0.06 - Risk in **non-vaccinated group** = 12/100 = 0.12 - **RR = 0.06 / 0.12 = 0.5** **Interpretation:** An RR of **0.5 indicates a protective effect** of vaccination. Vaccinated individuals have **half the risk** (50% reduced risk) of developing malaria compared to non-vaccinated individuals. *Incorrect: 2* This is the **inverse** of the correct RR, calculated as 0.12/0.06 = 2 (risk in non-vaccinated / risk in vaccinated). This would incorrectly suggest vaccination **doubles the risk** of malaria, which contradicts the data showing vaccination is protective. *Incorrect: 1.5* This value does not result from the correct RR formula using the given incidence rates (0.06 vs 0.12). This may arise from incorrect formula application or confusion with other epidemiological measures like the **Odds Ratio**. *Incorrect: 1.7* This is not the result of standard RR calculation based on the incidence rates of 0.06 and 0.12. It represents a **calculation error** and has no epidemiological meaning in this context.
Question 33: A gym owner observes that individuals who drink iced tea during their workouts tend to lose more weight. What is the nature of this relationship?
- A. Indirect (Correct Answer)
- B. Direct
- C. Spurious
- D. Relative
Explanation: ***Indirect*** - This relationship is considered **indirect (mediated)** because the iced tea consumption operates through an intermediary mechanism to produce the observed outcome - The proposed pathway: iced tea (A) → improved hydration/sustained energy during workout (B) → enhanced exercise performance (B) → increased weight loss (C) - In an **indirect relationship**, the exposure influences the outcome through one or more **mediating variables** rather than acting alone - While **confounding** (spurious association) is also plausible in this observational scenario, the question assumes a mediated causal pathway exists *Spurious* - A **spurious association** occurs when two variables appear related only because both are independently caused by a **third confounding variable** - Example: If highly motivated individuals both drink iced tea AND exercise more intensely, the tea itself may not cause weight loss—both behaviors are driven by motivation - This is actually a **very plausible alternative explanation** for this observational finding - However, if we accept that iced tea has a true physiological effect on workout quality (hydration/performance), then the relationship becomes indirect rather than spurious *Relative* - **"Relative"** is not a type of epidemiological relationship - This term describes **measures of association** (relative risk, relative rate, odds ratio) used to quantify relationships - It does not classify the nature or causal structure of an association *Direct* - A **direct relationship** means the exposure directly causes the outcome without any intermediary steps (A → C) - Weight loss fundamentally results from **caloric deficit** (energy expenditure > intake), primarily driven by physical activity and diet - Iced tea alone, without the mechanism of improved workout performance, would not directly cause significant weight loss - Since the weight loss depends on the workout as an intermediary step, this is not a direct relationship
Question 34: A study was conducted in 3 communities (across 3 states) to measure the mean blood pressure in each community. Health workers were assigned to visit each house in the 3 communities. The mean blood pressure of each community was then compared. What is the study design called?
- A. Case-control
- B. Ecological study
- C. Cross-sectional (Correct Answer)
- D. Cohort
Explanation: ***Cross-sectional***- This design takes a **snapshot** of the population (the 3 communities) at a specific time, simultaneously assessing the current status of the outcome (mean **blood pressure**) in each house.- The goal is to determine the **prevalence** of a characteristic (mean blood pressure) within the defined population by studying individuals (each house) within them.*Case-control*- This design requires comparing individuals who have the outcome (**cases**) to those who do not (**controls**) by looking **retrospectively** for past exposure differences.- The current study does not involve selecting groups based on outcome status (e.g., high BP vs. normal BP) to investigate an antecedent exposure.*Cohort*- A **cohort** study follows groups based on their **exposure status** over a period of time to calculate the **incidence** (rate of new cases) of a specific outcome.- This study measures current blood pressure status in a single visit; it does not track individuals longitudinally to see who develops hypertension later.*Ecological study*- This type of study correlates aggregate data (mean outcomes) across different population groups (e.g., states or countries), where the units of analysis are **populations**, not individuals.- Although the final comparison involves community means (ecological data), the design phase involving detailed collection of individual BP data by visiting **each house** is characteristic of a primary **cross-sectional** survey.
Question 35: Which of the following is a technology-based surveillance system for tuberculosis (TB) in India?
- A. Dots99
- B. DOTS
- C. Nikshay (Correct Answer)
- D. Nischay
Explanation: ***Nikshay***- **Nikshay** is the mandatory, web-based, real-time surveillance system used across India for the notification and comprehensive management of all tuberculosis (TB) patients, both from public and private sectors, under the National TB Elimination Programme (NTEP).- It integrates various data points, including patient details, diagnostic reports, treatment adherence, and outcomes, fulfilling the requirement for a **technology-based surveillance system**.*Nischay*- This name is not associated with the official national technology platform for TB surveillance in India; the official platform is called **Nikshay**.- There is no widely recognized national health vertical exclusively named Nischay related to TB control; the term might be confused with other local or foundational initiatives.*Dots99*- This term is not a recognized or official abbreviation for any technology-based surveillance platform or major component of the Indian TB control effort.- While **DOTS** is fundamental to treatment success, the suffix '99' does not correspond to a specific digital surveillance system.*DOTS*- **DOTS** stands for **Directly Observed Treatment, Short-course**, which is the internationally accepted strategy for managing TB treatment and ensuring patient adherence, *not* a technology platform.- Although central to the TB program, DOTS describes the treatment supervision mechanism, differing from **Nikshay's** role as the digital data management and surveillance tool.
Question 36: Wasting in a child is assessed by which of the following measures?
- A. Height-for-age
- B. Weight-for-age
- C. Weight-for-height (Correct Answer)
- D. Height-for-weight
Explanation: ***Weight-for-height***- This index is the standard measure used to assess **wasting** (acute malnutrition) as it determines if a child's weight is appropriate for their length or height, regardless of their age.- A low **Weight-for-height** Z-score strongly indicates that the child is too thin for their height, often reflecting recent severe weight loss or inadequate energy intake.*Weight-for-age*- This measure assesses whether a child is **underweight**, which is a composite parameter reflecting both acute (wasting) and chronic (stunting) malnutrition.- Because it is influenced by height (stunting), it does not specifically isolate **wasting** as the primary nutritional concern.*Height-for-weight*- This is not a standardized or clinically recognized anthropometric index used by global health organizations (like WHO) for assessing nutritional status.- The ratios commonly used are weight-for-height, weight-for-age, and height-for-age. *Height-for-age*- This index is the gold standard for assessing **stunting** (chronic malnutrition), revealing if a child is too short relative to the expected height for their age.- It indicates long-term nutritional deprivation and past growth faltering, not the current state of acute malnutrition (wasting).
Question 37: For what population size is an urban Primary Health Centre (PHC) typically intended?
- A. 1 per 100,000
- B. 1 per 250,000
- C. 1 per 200,000
- D. 1 per 50,000 (Correct Answer)
Explanation: ***1 per 50,000***- This is the standard population norm recommended by the Government of India for establishing an **Urban Primary Health Centre (UPHC)**.- The UPHC acts as the first referral unit for basic health needs, providing comprehensive **primary healthcare services** to this specified population size.*1 per 100,000*- This population norm is typically associated with the establishment of a **Community Health Centre (CHC)** (or sometimes an Urban CHC), which serves as a secondary care unit.- A PHC is designed to serve a smaller, more manageable catchment area to ensure effective outreach and **service proximity**.*1 per 250,000*- This much larger population size is often used as the norm for establishing higher-level facilities like **Sub-District Hospitals** or specialized referral institutions.- Implementing a PHC model for 250,000 people would violate the principles of accessible and decentralized **primary healthcare**.*1 per 200,000*- This population size is substantially higher than the mandated coverage area of **50,000 for an urban PHC**.- Utilizing this norm would severely compromise the crucial indicators of quality and accessibility of **primary care** services within the urban context.
Question 38: What were the goals for Maternal Mortality Rate (MMR) and Infant Mortality Rate (IMR) as per India's National Health Policy 2017 intermediate targets?
- A. 100/30
- B. 30/100
- C. 70/30 (Correct Answer)
- D. 30/70
Explanation: ***Correct: 70/30*** - India's **National Health Policy (NHP) 2017** set the target of achieving an **MMR of 70** per 100,000 live births by **2025** and an **IMR of 30** per 1,000 live births as an intermediate goal - These targets align with **Sustainable Development Goal (SDG 3.1)**, which aims to reduce global MMR to less than **70** per 100,000 live births by **2030** - The numerically higher value (70) represents MMR per 100,000, while the lower value (30) represents IMR per 1,000 live births, reflecting the different denominators used *Incorrect: 30/70* - This reverses the targets incorrectly: **30 for MMR** and **70 for IMR** - An MMR of 30 per 100,000 would be unrealistically low for India's intermediate targets (though it represents excellent maternal health) - An IMR of 70 per 1,000 live births is unacceptably high and far above established national goals *Incorrect: 100/30* - While the **IMR target of 30** is correct and aligned with NHP 2017 - The **MMR target of 100** per 100,000 live births is too high; both SDG 3.1 and NHP 2017 aim for **70 or less** - An MMR of 100 does not reflect India's ambitious maternal health improvement goals *Incorrect: 30/100* - This combination sets unrealistic and contradictory targets - **MMR of 30** is below even the global SDG target and not the NHP 2017 intermediate goal - **IMR of 100** per 1,000 live births is far too high, approximately 3-4 times higher than the actual target of 28-30
Question 39: Which of the following is the vector responsible for transmitting Orientia tsutsugamushi?
- A. Mite (Correct Answer)
- B. Flea
- C. Tick
- D. Louse
Explanation: ***Mite***- *Orientia tsutsugamushi*, the causative agent of **scrub typhus**, is transmitted to humans by the bite of the **larval stage** (chiggers) of mites belonging to the Trombiculidae family, such as *Leptotrombidium deliense*. - Mites are crucial in the infectious cycle because they maintain the pathogen through **transovarial transmission**, acting as both the **vector** and the **reservoir**. *Tick* - Ticks are the vectors for other rickettsial diseases, most notably **Rocky Mountain spotted fever** (*Rickettsia rickettsii*) and tularaemia. - Tick-borne infections typically involve different reservoirs (e.g., small mammals, deer) and produce distinct clinical syndromes from scrub typhus. *Louse* - Lice (specifically the body louse) are the vectors for **epidemic typhus** (*Rickettsia prowazekii*) and trench fever. - Transmission of louse-borne pathogens involves scratching infectious feces into the skin, which is not the mechanism for *Orientia tsutsugamushi*. *Flea* - Fleas, particularly the oriental rat flea, transmit **murine typhus** (*Rickettsia typhi*) and **plague** (*Yersinia pestis*). - This type of vector is typically associated with peridomestic rodents, contrasting with the outdoor, vegetation-associated exposure risk characteristic of **scrub typhus**.
Question 40: What concentration of fluoride is typically associated with causing crippling fluorosis?
- A. > 10 mg/L (Correct Answer)
- B. > 1.5 mg/L
- C. > 3 mg/L
- D. > 6 mg/L
Explanation: ***> 10 mg/L***- Crippling fluorosis, the most severe form of **skeletal fluorosis**, occurs due to chronic, high-level fluoride ingestion, typically associated with concentrations **above 10 mg/L** consumed over 10–20 years.- This condition involves widespread **osteosclerosis**, calcification of ligaments and tendons, and often leads to significant joint immobility and neurological symptoms due to **spinal cord compression**.*> 6 mg/L*- This concentration is generally associated with severe **dental fluorosis** and the onset of early-stage (non-crippling) **skeletal fluorosis**.- While chronic exposure at this level causes definite skeletal changes, it usually falls short of meeting the criteria for **crippling fluorosis** (Stage III).*> 3 mg/L*- Concentrations around 3 mg/L are strongly linked to moderate to severe permanent aesthetic changes consistent with **dental fluorosis**.- Although bone fluoride accumulation occurs, this concentration is usually insufficient to cause the radiological or clinical manifestations of **skeletal fluorosis** or bone pain.*> 1.5 mg/L*- This concentration is just above the optimal range for caries prevention (0.7–1.2 mg/L) and is generally the threshold for clinically apparent **dental fluorosis**.- It is not associated with **skeletal fluorosis**; the WHO maximum acceptable limit for fluoride in drinking water is often set near this value to prevent severe mottling.