Rahul nice videos. I am working in cancer epi, and teaching population epidemiology. You did a nice job. If you don´t mind I will recommend your youtubes in case the students would like to hear an alternative way of explanation! Just one comment... in minute 4 you discuss the persons at risk, but you omit the person-time (you just take the number of persons). Why did you not take the time at risk during the 10 years into account in your explanation?
Hi Rahul, I am curious why you DIDN'T count the number of person years in your calculation of incidence in this video whereas in your last example (your other video) of incidence you did?
Not having cancer within the specified time does not mean that they are not at risk, it just means that the disease has not yet occurred. I think 6 people were taken for this reason.
You are genius, ..this is exactly what I needed, explaining topics with relevant examples makes so much sense of what we are actually studying ! Thank you so much for putting up this video.
Very well simplified, however, I though the denominator for the incidence would have been 5 and not 6 considering that the 6th person developed cancer after the 10 year period...?
Sarah, Greetings. Yes, some conditions such as myocardial infarction, fracture, adverse reactions, etc may have multiple episodes occurring within the same individual. First, for us to consider multiple episodes within an individual, he/she must have full recovery between episodes. Once this criteria is fulfilled, the usual way of calculation is via person-duration or person-years. For instance, 18 myocardial infarctions (MIs) were experienced among 157 individuals followed up each for two years. In that arm, during a period of 314 person-years of follow-up, the rate is (18 divided by 314) = 0.057 per person-year or 5.7 per 100 person-years. The 18 MIs arose through 12 patients having single MIs and 3 patients each having 2 MI. So, to your query, if there are multiple cases occurring, yes - the incidence would go up.
dr patwari were do you get 0.66 i am preparing for usmle step 3 i find bio stats really tough i listen to all your tapes they are great can you please tell me how it is 0.66
@@sanadbenali6993 Greetings. Risk means probability of acquiring the condition and importantly must not have the condition in question at the start of the time frame. Six individuals at the start of the time frame, did not have the condition YET, so these six is calculated as the denominator irrespective of whether they end up with the condition.
@@albiner1999 how would you justify calculating the control as a at risk a guy never gets cancer even after years with followup which i think Is bad protocol that person is no longer in a study both the control and the guy who got cancer later would be a bad choice right?
It's the time frame in which we are counting the risk, ....these people had the risk and caught the disease , both within the the time considered , .......in case if you say those who caught the disease in the given time (who previously were at risk before acquiring the disease) shouldn't be counted ...then you will end up counting only those people who are not affected by the disease , which in this example will be 1 ..and that would be a different entity
Thank you for these videos, I am currently working on an MPH and have been struggling with my intro Epi course this semester. These have been so helpful!
Thanks, I'm glad it helped.
10 years later. It’s still helping a lot more people thank you
Rahul nice videos. I am working in cancer epi, and teaching population epidemiology. You did a nice job. If you don´t mind I will recommend your youtubes in case the students would like to hear an alternative way of explanation! Just one comment... in minute 4 you discuss the persons at risk, but you omit the person-time (you just take the number of persons). Why did you not take the time at risk during the 10 years into account in your explanation?
Hi Rahul, I am curious why you DIDN'T count the number of person years in your calculation of incidence in this video whereas in your last example (your other video) of incidence you did?
Incidence is different from incidence rate
Hallelujah I came across this video. Strugglong with the denominator of incidence and this helped thank you!
i still dont get how you got "6" people at risk of cancer at 5:05, it says "never had cancer" .... shouldn't it be 5 cases of 'at risk for cancer?'
Not having cancer within the specified time does not mean that they are not at risk, it just means that the disease has not yet occurred. I think 6 people were taken for this reason.
Prevalence. Errbody is involved at x time. Count them all including the RIPs, substract those.
You are genius, ..this is exactly what I needed, explaining topics with relevant examples makes so much sense of what we are actually studying ! Thank you so much for putting up this video.
I will guess you are a musician, loving you sister.😎
thank you sir...this helps me understand my report :) god bless
Awesome content. Very direct, concise. Thank you Mr.Rahul Patwari!
your videos are great! have you considered making videos on the pathology of various disorders?
pathology and pathogenesis*
Really helpful! Thank you!
Finally made sense! Thank you
Perfect illustration, thanks a lot!
Plzz give me right option of this
Epidemiology is used to determine the...............Of a condition.
A. Prevalence
B. Incidence
C. Both
Very well simplified, however, I though the denominator for the incidence would have been 5 and not 6 considering that the 6th person developed cancer after the 10 year period...?
If an individual has multiple new cases does that affect the incidence?
Sarah, Greetings. Yes, some conditions such as myocardial infarction, fracture, adverse reactions, etc may have multiple episodes occurring within the same individual. First, for us to consider multiple episodes within an individual, he/she must have full recovery between episodes.
Once this criteria is fulfilled, the usual way of calculation is via person-duration or person-years.
For instance, 18 myocardial infarctions (MIs) were experienced among 157 individuals followed up each for two years. In that arm, during a period of 314 person-years of follow-up, the rate is (18 divided by 314) = 0.057 per
person-year or 5.7 per 100 person-years.
The 18 MIs arose through 12 patients having single MIs and 3 patients each
having 2 MI.
So, to your query, if there are multiple cases occurring, yes - the incidence would go up.
Think the incidence calculation is wrong! I get 50%, (3 cases over 6 at risk)
There are 4 new cases. So, it should be 4 over 6, right?
Thank you sir for your explanation. I've got clear understanding for incidence and prevalence.
Thank you sir...You made everything easy :)
Thank you sir ❤ your explanation is easy and to the point helped me a lot
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hi wanted to ask, if you were not given a duration and was asked to calculate overall prevalence, it should just be the prevalence formula right?
Writing 4 out of 6 as 0.67 would have made it a little easier to follow, even though your meanng was clear.
What measure of disease frequency combines prevalence and incidence?
Thank you for this presentation,, it's helpful somehow
This is the point prevalence. I think the result is different if it is period prevalence. Great video.
This video is 10 years old but it just saved me in my graduate level epi class!
VERY Good explanation of incidence and prevalent
THANK YOU SO MUCH THIS REALLY HELPED
dr patwari were do you get 0.66 i am preparing for usmle step 3 i find bio stats really tough i listen to all your tapes they are great can you please tell me how it is 0.66
6 people were at risk; 4 got cancer during the time frame. 4/6 = 0.66
Dee Smith one of the six never got cancer how does the study chart show he is at risk not just a fluke or something
@@sanadbenali6993 Greetings. Risk means probability of acquiring the condition and importantly must not have the condition in question at the start of the time frame. Six individuals at the start of the time frame, did not have the condition YET, so these six is calculated as the denominator irrespective of whether they end up with the condition.
@@albiner1999 how would you justify calculating the control as a at risk a guy never gets cancer even after years with followup which i think Is bad protocol that person is no longer in a study both the control and the guy who got cancer later would be a bad choice right?
Thank you!! I have an epi exam coming up and this really helped
Thanks to you I finally got it
Hello can u help me in some exercises
Thank you for your help!
DEATH FACE 🤡🤣😂🤯👍
people that had cancer cannot be at risk because they already have it now. i don't get it how he counted them with the people at risk that's confusing
It's the time frame in which we are counting the risk, ....these people had the risk and caught the disease , both within the the time considered , .......in case if you say those who caught the disease in the given time (who previously were at risk before acquiring the disease) shouldn't be counted ...then you will end up counting only those people who are not affected by the disease , which in this example will be 1 ..and that would be a different entity
thank you sir
You are awesome !
proper and well explained
Thank you
Thanks. Great explanation !!!!
تههق
Thank you for these videos, I am currently working on an MPH and have been struggling with my intro Epi course this semester. These have been so helpful!
Thank you so much
Thanks dear
Simple and straight forward. Thank you.
thank u alot ,
Thank you!!!
THANK YOU!!!
good