Bio 256 Exam 2 Flashcards
(54 cards)
Epiidemiology
Study of frequency of distribution of disease in human populations
Random Fluctuation and what is its connection to p values and the chi square test
need to have a large sample size to rule this out
p values and chi square test
the difference between what was observed and what expected was actually due to a real difference not random
Confounding variables
a factor that affects the rink of developing cancer and is linked in some way to the factor being investigated
ie. age or smoking
Detection bias
failure to use consistent and equivalent procedures to measure incidence rates
Publication bias
journals don’t punich the absence of relationships or lack of cause-effect. So we don’t see that data
Experimenter bias
the scientist isn’t remaining objective
ie. viewing data thru rose tinted glasses
Selection bias
nonrandom volunteers
Retrospective Studies
what is it and whats its other name
Assess past exposure of people already with cancer
aka: “case-control studies”
Prospective Studies
and its other name
Follow people into the future to see who develops cancer
aka: cohort studies
a “disease free cohort” following them to see what reasons they might develop cancer
- need a large sample size
- some people will refuse to participate after a while
recall bias
and what studies are susceptible to this
people may not remember what happened to them
retrospective studies are susceptible to this bias
post hoc fallacy
conflating correlation with causation
How to demonstrate cause and effect
Show statistical significance
Demonstrate dose-response relationship
Demonstrate magnitude (it has to at least double the rate of cancer)
Randomized trials
why is it a problem on humans. who is it used on?
not ethical in humans it will kill them
is for animals because rats cant feel lol
Ames test
effective way of finding cause and effect
rapid screening test of possible chemical carcinogens
Main risk for human cancer
Age
Environmental and lifestyle (diet smoking eating)
alcohol
food choices
pesticides in our daily foods
synthetic and natural alike
red meats saturated fats
radiation exposure
oncogenic virus
viruses that cause cancer
rouse sacarcoma, hpv, epstein barr, hepatitis b and c
3 principles of chemical carciongens
-exposure — delay —– cancer
-dose dependence
-chemical carcinogens have organ specificity
workplace carcinogen
cancer causes agents the work place
asbestos is the big one
asbestos penetrates the lung and lodges in the mesothelial cells
modelsof dose cancer relationship
linear: increase dose - increase rate
threshold: no risk low, linear after threshold met
hormetic: u-shaped, low doeses decrease rate while high doses increase
Polycyclic aromatic hydrocarbons (PAHs)
Mechanism of Chemical Carcinogenesis
fused benzene rings
coal tars, soots, oils when not completely burned
Mechanism of Chemical Carcinogenesis
Aromatic amines
Mechanism of Chemical Carcinogenesis
n-nitroso
Mechanism of Chemical Carcinogenesis
nitrites nitrates
may be converted into carcinogens in stomach
in fruits, an pacakged meat
