6- epidemiology

What is epidemiology?

Study of distribution and determinants of health related events in specified population

How it can be applied to health problems

In what 5 ways can epidemiology be applied?(objectives)

Describe distribution and magnitude of diseases

Identify causes

Study natural history and prognosis

Evaluate new preventative and therapeutic approaches

Allow development of public policies

Smokers have a …. greater risk of developing lung cancer compared to non smokers

9

1958- 44% tobacco linked to cancer

1968- 78%

Why is epidemiology and health promotion important?

People should have control over their health

Correct design of epidemiological research

Proper interpretation of research

Avoid misinformation so no public confusion

What is incidence and what type of studies is it useful in?

Number of new cases in a disease free group

Causality studies

increases when more intense risk factors (smoking, perio disease)

What is the difference between cumulative incidence and incidence rate or density?

Proportion of individuals developing the disease during follow up period- fixed cohort

Vs ratio between number of new cases during follow up period and total observation time- dynamic cohort- allows new entries

What is prevalence?

Proportion of individuals suffering from a disease at a given time

What is an epidemiological index?

Numerical value specifying health status through a graded scale

Standardises data collection

Can have individual or population indices

What are the 5 characteristics of an epidemiological index?

Validity

Clarity

Reliability

Sensitivity- detect small variations

Acceptability- no discomfort

What is the prevalence of gingivitis?

Global- 50%

Children- 70-80%

Adults- 90%

Depends on socioeconomic status, access to dental care, education

What are 8 risk factors for gingivitis?

Poor oral hygiene

Age

Genetic factors

Tobacco use

Pregnancy

Systemic diseases

Medications

Stress

What is the prevalence of periodontitis?

Global- 45%

Increases with age- severe in 40-60

65yrs- 70-80%

Adults- 30%

What are 7 risk factors of periodontitis?

Poor oral hygiene

Smoking

Genetic factors

Systemic diseases

Stress

Socioeconomic

Medications

How do you measure periodontal disease?

Calibrated probe

What does the Silness and Loe index measure?

Plaque thickness along gingival margin

Dry with a light air jet

No plaque disclosing agent

Examined in 4 units- B, P/L, M, D