Epidemiology in Community Medicine

Introduction

• Lecturer: Dr. Priyanka
• Platform: Unacademy
• Topic: Epidemiology in Community Medicine
• Structure: 2-hour daily sessions over 4-5 days
• Focus: Measurements of mortality and morbidity

Definition of Epidemiology

• Etymology:
  • 'Epi' means among
  • 'Demos' means people
  • 'Logic' means study
• Definition: Study of the distribution and determinants of health-related events in specific populations.
• Epidemiological Approach: Questions to answer
  • What is the event?
  • When did the disease occur?
  • Where did the disease occur?
  • Who is affected?
  • What is the extent?
  • Why did it occur?
  • How can it be controlled and prevented?

Hypothesis Testing

• Create a hypothesis and test it
• Two outcomes: Hypothesis is right or wrong
• Methods of testing the hypothesis will be discussed

Basic Mathematical Concepts

• Difference between rate, ratio, and proportion

Rate

• Formula: (Numerator/Denominator) * Multiplier
• Characteristics:
  • Multiplier can be 1000, 10,000, etc., but not 100
  • Includes a time specifier
  • Example: Death rate
  • Definition: Occurrence of a particular event in a population over a specified time

Ratio

• Formula: Numerator/Denominator
• Characteristics:
  • Numerator and denominator are independent quantities
  • Multiplier is not used
  • Time specifier can be present or absent
  • Example: Sex ratio (number of boys to number of girls)
  • Definition: Relationship in size of two quantities

Proportion

• Formula: (Numerator/Denominator) * 100
• Characteristics:
  • Numerator is part of denominator
  • Multiplier is always 100
  • No time specifier; it is instantaneous
  • Example: Percent of children with scabies
  • Definition: A part of the whole expressed as a percentage

Quick Comparison

• Rate: Numerator is part of denominator, Multiplier ≠ 100, Includes time, Example: Death rate
• Ratio: Numerator and denominator are independent, No multiplier, Time can be any, Example: Sex ratio
• Proportion: Numerator is part of denominator, Multiplier = 100, No time specifier, Example: Percentage of children with scabies

Measures of Mortality

Definition

• Mortality: Death as an event in a given time frame
• Morbidity: Departure from well-being, Presence of disease

Six Indicators of Mortality

1. Crude Death Rate (CDR)
2. Specific Death Rate (SDR)
3. Proportional Mortality Rate (PMR)
4. Survival Rate
5. Case Fatality Rate (CFR)
6. Standardized Mortality Rate (SMR)

Crude Death Rate (CDR)

• Formula: (Number of deaths / Mid-year population) * 1000
• Definition: Includes all deaths regardless of age, gender, cause
• Characteristics: Simplest measure, broad indicator of health status
• Example: India's CDR was 7.4 per 1000 (2011 data)

Specific Death Rate (SDR)

• Formula: (Number of deaths due to specific cause or group / Mid-year population) * 1000
• Types:
  • Disease-specific
  • Age-specific
  • Period-specific
• Definition: More refined focus on specific causes or groups
• Advantages: Good for comparison
• Example: Diabetes-specific death rate vs. TB-specific death rate

Proportional Mortality Rate (PMR)

• Formula: (Number of deaths due to a specific cause / Total deaths) * 100
• Definition: Proportion of deaths due to specific cause among total deaths
• Advantages: Indicates burden of disease
• Example: Comparing burdens of TB, diabetes, cancer

Quick Comparison

• CDR: Simplest, includes all deaths
• SDR: Good for comparison, specific causes
• PMR: Indicates burden of disease, proportion of deaths

Announcements & Conclusion

• Break for 10 minutes
• Join back at 10:45 AM for continuation and numerical problem solving
• Install Unacademy Learner's App for more detailed lectures and notes
• Use code "Sachdev10" for unlocking free classes and discounts on subscriptions
• Upcoming events: All India Mock Test on February 26, Combat Test on February 19