AS - Non-communicable dieases Flashcards
Four types of non communicable dieases
Cancer
Chronic Respiratory Diseases
Cardio Vascular Diseases
Diabetes
Risk
Number of people experiencing an event / (devided by) Number of people exposed to the risk factor
Risk: Conditions, behaviour, hereditary
Conditions: Other medical conditions that increase the risk of a NCD
Behaviour: Lifestyle choices e.g. smoking
Heredity: Family history
Stroke risk factors
Conditions: Increased age, high blood pressure
Behaviours: Excess salt intake, physical inactivity, excess alcohol
Hereditary: sickle cell disease
Lung Cancer risk factors
Conditions: Exposure to radiation, increased age
Behaviours: smoking, radon gas in home
Hereditary: first-degree family member with lung cancer
Asthma risk factors
Conditions: Having another allergic condition
Behaviours: Being overweight, smoking, exposure to allergens
Hereditary: Having a blood relative with asthma
Type 2 diabetes risk factors
Conditions: older than 45, gestational diabetes
Behaviours: physically active less than 3 times a week, being overweight
Hereditary: parent/sibling with diabetes
Epidemiological evidence and cancer
Strength of association, temporality, consistency, biological plausability, coherance, specificity, dose response relationship,experimental evidence, analogy
Strength of association
The stronger the relationship between independent variable (smoking) and the dependent variable (lung cancer) the less likely the relationship is due to another variable)
Temporarily
The exposure must precede the disease by a reasonable amount of time. There is a time delay between an increase in smoking and an increase in lung cancer
Consistency
multiple observations of association with different people under different circumstances
Biological Plausability
It is easier to accept an association as casual when the conclusion is supported by known biological facts.
Coherance
A “cause and effect” interpretation is possible if all the available data from different types of experiments is consistent and there are no conflicting theories
Specificity
Ideally the effect (lung cancer) only has one cause
Dose response relationship
There should be a positive correlation between the dose and the disease
Experimental evidence
Any related research that supports the epidemiological findings adds to the “cause and effect” conclusion
Analogy
Sometimes a commonly accepted phenomenon in another area can be applied
Benign tumour
Slow growing tumours tend to be located in ONE SPECIFIC TISSUE. Cells don’t break off and spread to other parts of the body and so these tumours tend to be non-life threatening.
Malignant tumour
Rapidly growing tumour that can be very damaging if not detected early. Some cells can break off from the original tumour and spread to other tissues via lymphatic system or in blood plasma. - then described as metastatic and is now classified as cancer
Proto-oncogene
-Stimulates cell division
- normally requires growth factors as signals
Effects of mutation = Becomes an oncogene, triggers cell division regardless of appropriate stimulation
Tumour supressor gene
Prevent cell cycle from continuing when DNA error is identified
Effects of mutation: Cell divides regardless of DNA faults
3 types of mutagen:
Physical
Chemical
Biological
X-rays
CT Scan: patient lies on a platform which passes through the CT scanner, takes X-ray pictures from many angles
Mammogram: Breast X-ray between two plates an unusual lump shows up as a lighter area
Ultrasound
Uses sound waves to build up an image. It is particularly useful for detecting tumours in soft parts of the body. It is cheaper and more portable method than others
Pet scan
Patient injected with a radioactive substance which breaks down in the body emitting gamma waves. The most metabolically active parts emit the most gamma rays. The pattern builds up into an image
Biopsy
Piece of tissue is removed from the body to be analysed in a labatory for a definitive cancer diagnosis
Bone marrow biopsies may be taken from the hip bone under local anaesthetic
Soft tissue biopsies can be used when a lump can be felt under the skin or endoscopic biopsies can be carried out through the mouth or rectum
BRCA1 + BRCA2
Two genes that produce tumour suppressor proteins. As a result mutations in these genes can lead to cancer. Betwee 45 and 90% of women carrying these mutations will be diagnosed with breast cancer during their lifetime.
HNPCC
There are mutations in five genes that normally repair mismatched DNA that may lead to hereditary non-polyposis colorectal cancer. About 70% of women and 90% of men carrying this mutation will develop bowel cancer by the age of 70 years. They are also at enhanced risk of cancer of the uterus, gastrointestinal tract and ovary
A positive gentic test
Gene mutation found
Doesn’t mean definitely get cancer
Continued screening reduces risk
Consultation with genetic counsellor helps patient understand risks
A negative genetic test
Gene mutation not found - No increased risk
Increase screening and test again
Survivor guilt
Treating Cancer: Mastectomy
Surgical removal of the whole breast
Treating Cancer: Radiotherapy
Ionising radiation kills more cancer cells than normal cells as they are more actively growing
Treating Cancer: Lumpectomy
Surgical removal of the tumour and some of the surrounding tissue
Treating Cancer: Chemotherapy
Drugs that are toxic to dividing cells. Cancer cells are dividing at a faster than normal cells
Treating Cancer: Immunotherapy
Herceptin is an antibody that attaches to receptors so preventing growth factors attaching
Treating Cancer: Complementary therapies
including meditation, hypnotherapy and aromatherapy. A holistic approach that seeks to treat the whole person. Often used alongside medical treatments
Treating Cancer: Hormone treatment
which prevents oestrogen attaching to the cancer cells by blocking their receptors
