Natural History of Disease

Question 1

Fundamental question of epidemiology

Answer 1

Exposures connection to outcomes

Question 2

Risk factors for disease

Answer 2

Increases the probability of an individual developing a disease or health condition

Can also have risk factors for different stages of disease process (prognosis, morbidity, etc.)

Question 3

Types of risk

Answer 3

Environmental
Chemical
Physiological
Genetic 
Social

Question 4

Etiologic Factor

Answer 4

The cause or set of causes of disease or health condition.

Biologic understanding of how cause of disease leads to structural and functional physiological changes that result in disease (Pathogenesis)

All etiologic factors are risk factors but not all risk factors are etiologic factors

Question 5

Natural history of disease

Answer 5

Time of exposure to causal agent (etiological factor) -> clinical outcome

Question 6

Incubation Period

Answer 6

The period between receipt of infection to the time of onset of clinical illness

Concept also applies to non-communicable diseases (called “latency period”)

Question 7

Primary Prevention

Answer 7

To prevent the initial development of disease among disease-free individuals

Remove causes of disease:
immunization
health/policy promotion

Question 8

Secondary Prevention

Answer 8

Early detection of existing disease among asymptomatic individuals to reduce severity and improve outcome

Preclinical phase

Screen for, detect, and treat diseases early ex. mammogram
(no symptoms)

Question 9

Tertiary Prevention

Answer 9

To reduce the impact of disease among diseased individuals who have already been diagnosed

Clinical phase

Symptoms present, disease diagnosed

Treat clinical phase to prevent death or complications

Question 10

Signs

Answer 10

Signs are evidence of disease observed on physical examination

Question 11

Symptoms

Answer 11

Symptoms are indications of disease reported by the patient

Question 12

Diagnosis

Answer 12

Detection of existing disease among individuals who are already exhibiting clinical symptoms.

*not a level of prevention

Signs: observed on clinical exam (objective)
Imaging technology
Laboratory tests of biological specimens
Biopsies
Precipitating factors/triggers
Symptoms: reported by patient (subjective)

Question 13

Risk Factor Identification

Answer 13

Identify a factor or set of factors that increase the risk of disease

Risk factors vary in terms of impact on disease occurrence

Some risk factors are modifiable