28 - The Environment as a Cause of Disease Flashcards
1
Q
What are environmental causes of disease
A
- Chemical (heavy metal, air pollution, asbestos)
- Drugs (tobacco, ethanol, therapeutic drugs)
- Physical agents (trauma, thermal injuries, radiation)
- Nutritional deficiencies
2
Q
Correlation vs causation
A
Correlation does not equal causation (but it may provide a hint)
3
Q
Bradford hill considerations
A
- Strength of association
- Reproducibility
- Specificity of key event to the disease
- Temporality (cause before disease)
- Gradient (dose response)
- Plausibility (biology)
- Coherence (with natural history of disease)
8.Experimentation - Analogy (similar known causes)
4
Q
Asbestos pathogenesis
A
- Reactive oxygen species (catalysed by surface iron, macrophages attempt digest)
- Direct interaction (surface charge absorb proteins, DNA, RNA)
- Chronic inflammation
5
Q
Lead
A
- Disruption of heme synthesis due to affinity for sulfhydryl groups (→ anaemia)
- Competition with Ca-mediated messaging (→ neurotoxicity)
- Cell membrane transport interference (→ hemolysis, renal toxicity)
- Generation of hydrogen peroxide in endothelium (→ hypertension)
6
Q
Occupational chemical agents
A
Cobalt, cadmium, mercury, uranium etc
7
Q
Carbon monoxide
A
- Colourless, odourless, non-irritating
- from incomplete combustion of carbon
sources
8
Q
Mechanisms of toxicity of carbon monoxide
A
- Combines with haemoglobin to form carboxyhaemoglobin, reducing the amount of haemoglobin available to carry oxygen
- CO binds to myoglobin and cytochrome oxidases
and may impair their ability to utilise the oxygen they receive
9
Q
UV radiation
A
- Non-ionising but can alter chemical bonds (oxygen radicals, direct DNA damage)
- Sunburn (cell death due to induction of apoptosis)
- Collagen damage
