diet and cancer Flashcards
cancer
- uncontrolled cell division
- cells fail to differentiate
- tumours will develop
causes of cancer
mutations or loss of genes
rare genetic defects inherited
risk of cancer increases with age
methods to study cancer
cellular models animal studies human studies (epidemiological and intervention studies)
cell cultures
primary cells
immotalised cells
primary cells
cells isolated direcetly fro humans
sutible for short term experiments, due to short no cell divisions
immortalised cell lines
cells from cancerous tumours
unlimited cell division
advantages of cell studies
can look at function at a molecular level quick and cheap can look at ranges of doses genetically identicaly ccells unlimited quanitity
dis of cell studies
interaction with other cells lost
specliased tissue fucntion may be lost
cells can mutate themselves
animal studesi
correct speices needs to be picked
chemicals used to induce cancer in animal
can be genetically manipulated
ad of animal studies
relatively short lived imapct can be studies in montths
can be genetically manitpluated
tissues readuly available
easy to control diet intake
dis of animla studies
ethical
cant replicate environemtn or lifestyle
cannot replicate humans
types of human study designs (observational and expreimental)
Observational – epidemiological - ecological - cross sectional - cohort – (prospective/retrospective) - case control Experimental - RCT - cancer over decades, so cant easily design RCT to look at relationship between diet and cancer
what do epidemiolgy studies allow
production of evidence of an association between 2 varaibles
nutrtional epidemiology looks at
associations between diet and disease or risk factor for disease
population is defined by
time
geograpjy
socio economic status
ad/dis of ecological studies
Advantages
- useful to generate hypotheses
- large number of subjects
Disadvantages
- information not necessarily collected for the purpose of disease association
- population level no evidence of individual disease vs exposure
- other confounding factor
ecological studies are useful for
diet and cancer research
cross sectional studies measure
nutritional exposure and disease state in individuals
ad and dis of cross sectional studies
Advantages
- relates with individual exposure to the disease
Dis
- difficult to determine relationship between exposure and outcome – consequence or cause
- factors affecting disease survival may bias results
case control studies
individuals with disease/outcome compared to randomly selected control group from non diseased
ad/dis of case control studesi
effecient and quick cheaper than cohort or clinical trial dis - how representtive control group bias by diseased group? recall bias disease may alter behaviorur
types of cohort studies and what are tehy
prospective
- follows disease develpment
retrospective
- uses measures of past exposries
cohort
followed over time and rate of disease develipment observed in relation to exposure
ad/dis of cohuort
unbiased dis confounding factors large sample requried timely
