Lecture 4: Environmental basis of disease

Question 1

Epidemiology is the

Answer 1

Basic science concerned with the patterns of disease frequency in human population

-distribution of disease by person., place time

Question 2

assumptions made by epidemiology:

Answer 2

• Disease does not occur randomly

- Disease has identifiable causes

Question 3

Epidemiological research is used to

Answer 3

• Describe the health status of a population
• Explain the aetiology of disease
• Predict the disease occurrence
• Control the disease distribution

Question 4

Epidemiological triangle

Answer 4

• Host (intrinsic factors)
• Environment (extrinsic factors)
• Agent

Question 5

from triangle: HOST

Answer 5

• Genetic
• Age
• Sex
• Physiolocial state
• immunisiation
• behaviour

Question 6

from triangle: ENVIRONMENT

Answer 6

• physical

- socioeconomic

Question 7

from triangle: AGENT

Answer 7

• Nutritive
• chemical
• physical/radiation
• infectious

Question 8

epidemic -

Answer 8

widespread disease outbreak amongst a population

Question 9

pandemic -

Answer 9

epidemic crossing populations

Question 10

importance of migrant studies:

Answer 10

can look between immigrants and sons of immigrants and them in native countries to see if lifestyle and environment affects potential for disease (interplay of genetic and environmental factors)

Question 11

John Snow

Answer 11

(1813-1858)

-victorian surgeon & anaesthesiologist

Question 12

Vibrio Chloera

Answer 12

the organism that causes cholera was discovered 25 years after john snows death by ROBERT KOCH

Question 13

Cholera remains a serious problem in many countries due to

Answer 13

• Poor access to safe water and inadequate disposal of sewage.
• In unprepared communities fatalities to 50%.
• In well organised and prepared countries fatalities <1%
• ~6 million/yr die from diarrhoea (not all from cholera)

Question 14

Associations vs causations

Answer 14

things can be associated such as being french, smoking and lung cancer.
-but doesn’t mean if you’re french you will definitely have lung cancer

Question 15

mortality associated with smoking

Answer 15

• 320+ UK deaths every day from smoking, 120,000 per year
• 1/5 all deaths across all ages
• 7.5 years average loss of life expectancy
• 4 million deaths/year worldwide

Question 16

Major health consequences of smoking:

Answer 16

• Cancer;
• -lung
• -mouth, larynx, throat, oesophagus
• -bladder, cervix, kidney, pancreas
• Respiratory disease e.g. COPD (chronic obstructive pulmonary disease)
• Vascular disease
• -Coronary heart disease
• -Stroke
• -Peripheral vascular disease
• Pregnancy and birth complications

Question 17

smoking can lead to premature birth

Answer 17

• maternal endocrine/paracrine changes
• altered cell signalling
• restricted placental blood flow
• increased risk of membrane and rupture
• fetal hypoxia

Question 18

pulmonary emphysema =

Answer 18

enlargement of alveolar airspaces

with destruction of elastin in walls

Question 19

tobacco –> chronic chemical injury —> pulmonary emphysema

Answer 19

irritates –> alveolar macrophage –> neutrophil / chemotactic factors (IL8) –> proteases (inc elastase) –> tissue damage –> emphysema

Question 20

anti trypsin is mainly synthesised by hepatocytes but is also r

Answer 20

released from macrophages and neutrophils (some people are anti-trypsin deficient)

Question 21

smoking can lead to

Answer 21

• decrease in ciliary action
• chronic bronchitis increase excess of mucus
• -> both lead to infections –> tissue damage and emphysema

Question 22

smoking is highly addictive

Answer 22

• 70+% of smokers want to give up
• 50- % succeed before age 65
• 40% of heart attack smokers relapse while still in hospital within 2 days of intensive care
• 50% of patients with laryngectomies try smoking again
• 50% of patients with lung removed for lung cancer smoke again
• More than half of heroin and cocaine users and alcoholics rate smoking harder to quit

Question 23

in smoking whats the driving force behind addiction?

Answer 23

NICOTINE

Question 24

critical factors in determine whether exposure leads to disease

Answer 24

Chemical & biological composition
Shape & size of particles
Dose  - concentration and duration
Pre-existing health or genetic status
Concurrent exposure to other toxic

Question 25

pneumoconioses

Answer 25

• Lung disease caused by inhaled dust
• Dusts may be
• -Inorganic (mineral)
• -Organic
• Reaction may be
• -Inert (coal-miner’s)
• -Fibrous (asbestosis, silicosis)
• -Allergic (extrinsic allergic alveolitis)
• -Neoplastic (mesothelioma, lung carcinoma)
• Co-existing disease may aggravate reaction

Question 26

Asbestos produces several diseases

Answer 26

• Asbestosis
• Lung cancer
• Mesothelioma
• Cancer of
• -Stomach
• -Colon
• -Rectum

Question 27

the asbestos fibre + iron and calcium ==

Answer 27

“ferruginous body” (iron stain)

Question 28

Macrophage fibre ingestion ..

Answer 28

increases fibrogenic response (collage deposition by fibroblasts)