Chapter 2- BPK 140 - 140 notes PDF

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Chapter 2- Evaluating Health Claims -

Not all information is credible and therefore, must be evaluated before it is believed There are many types of evidence that may be presented to us that we must evaluate

Scientific Evidence -

Pre-scientific explanations used to be very superstitious The scientific view became more prevalent in Europe of the 18th and 19th century Scientists attempted to explain things in mechanistic terms- in terms of cause-and-effect mechanisms - Scientists are trained to follow a certain method in conducting a scientific experiment - The scientific method is a way of testing ideas under controlled conditions before accepting them as true Experimental Evidence - A scientist starts with a hypothesis- a statement that is phrased in a way that can be tested  Hypotheses are based on existing knowledge, logic, intuition, and educated guessing - A way to control the effects of other factors in an experiment is to use a control group who will get a placebo - The experimental group is the group that gets the experimental treatment - Control should be identical to experimental in every way except in what treatment they get - But, individual variability is still a factor- individuals vary in how their bodies respond to the similar situations - Good scientific studies usually have large sample sizes that have been randomly sampled - A placebo is something that has no effect on the variable being tested and that the subject cannot tell is different from the experimental treatment - A subject is the person participating in the experiment - A blind experiment is when subjects are blind to if they are receiving the placebo or the treatment - In a double-blind study both the subjects and the experimenter do not know who is getting the treatment, experimenter will only find out at the end which group got what  This minimizes the effects of the experimenter’s bias - Time can pose a problem in testing some hypotheses- example: some types of cancer have a long latent period, so the results of the experiment may not be apparent for years - There are also ethical considerations- it is not right to expose human subjects to procedures that increase risk of disease  An option is animal experimentation using mice/rats as they are relatively inexpensive and have short life spans

Another option is tissue cultures- getting tissue from swabbing the inside of a subject’s mouth and exposing those cells to different things  Computer modelling has also become more popular when simulating effects of different manipulations Epidemiological Evidence - Epidemiology is like medical detective work- ask questions to try and figure out what you are looking for - Can help discover risk factors - But you must also be careful not to assume causality, look for some things before saying something is causal:  Strength of the association  Dose-response- does mortality rate increase as smoking increases for example  Consistency  Temporally correct  Specificity  Biological plausibility 

Clinical Evidence -

This reflects what is seen in a clinic by physicians, dentists, chiropractors, psychologists, athletic trainers Often it is consistent with scientific evidence, but not all clinical procedures have been tested scientifically The best health care treatments come from clinicians and scientists working together

Personal Experience -

Information acquired through personal experience is not valid scientific evidence because conditions are not controlled But we tend to remember things that actually happened to us more easily than things we read in scientific papers But obviously, sometimes personal experience will go against scientific evidence

Anecdotal Evidence -

Anecdotal evidence is a story told by someone else It is as unscientific as personal experience

Critical Thinking -

There are some guidelines to look at when evaluating the credibility of the health claims Source  Is it a peer-reviewed journal  Does it have impact factors- how frequently have other authors cited this article

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Date  Is it recent information Author experience or qualifications  Does the author have any background/training in this Evidence  What evidence has the author presented to support main idea  Is it just an opinion or is there actual fact Bias  Does author present both sides of issue fairly  Does author have personal reason to persuade you to agree  Do they have a connection to something that makes you suspicious Logic  Is the reasoning sound Additional guidance  Discuss info with health care professionals  Determine purpose of site (sites ending in .com are usually selling something)  Try to find original source of information  Be careful with sites that ask for personal info  Check the links to see if they are working (does the author keep the site working regularly)  Beware of things that have a “Contact Us” link  Do they separate their opinion from fact Questions to ask yourself:  Is the claim too good to be true  What is the source of the claim and how credible is the source  Where was the claim published  How consistent is the claim with what you already know...