Environmental factors Flashcards
What is a carcinogen?
A cancer causing substance
What is the risk of a carcinogen dependent on?
Potency of the dose
Type of exposure - acute or chronic
Dose response - level of exposure
Why is air pollution a carcinogen?
Contains particulate matter, NO, SO, ozone, CO, PAHs.
They can be airborne or aerosols that accumulate in the lungs.
Highest risk is within urban areas. Low exposure areas have high rates due to the duration of exposure.
Why might soil and drinking water cause cancer?
If contaminated with arsinic or nitrates
How does tobacco increase the risk of cancer?
It contains carcinogens in both active and passive smoke. The addiction leads to chronic exposure.
The carcinogens bind to DNA or receptors to mutate signalling factors and reduce apoptosis and promote angiogenesis. Smoking shortens lifespan.
What factors in diet may increase risk of cancer?
Direct effect due to additives. Indirect effect through thee balance of diet. The agents are either classified as convincing or probable.
Processed meat and red meat on high intake.
What factors of the diet may reduce risk of cancer?
Fibre and fruit and veg when consumed at 5 servings a day. Particularly effective for colorectal cancer.
Tea, coffee, spices, vit and minerals, berries, nuts, antioxidants
What is the association between obesity and cancer?
Obesity carries a risk of DMII which will increase inflammatory cytokines and signalling.
Increase in adipocytes contributes to mutations in cells.
Increased lipogenesis produces FA that can activate signalling pathways in cancer cells.
What is the obesity-inflammation-aromatase axis?
Inflammation is linked to increased activity of NF-kB TF in tumour cells and therefor increases aromatase activity.
What is the function of aromatase?
An anzyme involved in the conversion of testosterone to oestrogen.
What is the effect of physical activity on risk of cancer?
PA reduces hormone levels of insulin and oestrogen and reduces level of inflammation and therefor decreases risk.
What is the correlation of alcohol and cancer?
High consumption increases relative risk, particularly affecting the GIT. Affects eastern and central European men most.
What type of cancer is caused by asbestos?
Pleural Mesothelioma - It is a fibrous silicate that can be inhaled. Symptoms may have a long delay before presentation.
How does an individuals occupation affect their risk?
It is dependent on dose-response relationship.
e.g. asbestos plants, mining
Why is it difficult to study the effect of diet and lifestyle?
Diet and lifestyle is constantly evolving and it is difficult to isolate one factor to study as they may inter-correlate.
