Page 1 of 1: biostats - i found this one tough plzz explain it!

sravya · Credits: 28740 My Scrapbook

a city with a population of 1,000,000.
10,000 have disesase x. there are 1000 new cases of disease x and 200 deaths each year from the disease. there are 2500 deaths per year from all causes. assuming no net emigration from or immigration to the city the incidence of disease x in this city is given by which of the following?

a) 200/1,000,000
b) 800/1,000,000
c) 1000/990,000
d) 2500/1,000,000
e) 10,000/990,000
f) 10,000/1,000,000

dr4jc · Credits: 4396 My Scrapbook

ans is b? cuz 1000-200 gives 800 new cases alive(incidence of the disease)... 200/2500 would give disease specific fatality rate...10,000/1,000,000 would be the point prevalence at the start...

ratnakar_potla · Credits: 5703 My Scrapbook My Reading List 2 Books

atleast i am sure there is error in the question either u typed or u saw.!!!!!!!!!
I am afraid if some one gives a fair explanation for the above the concept of incidence needs a revamp

bharatvedin · Credits: 4094 My Scrapbook

HI,

THERE IS NOPTHING WRONG IN THE Q.....

WAT IS INCIDENCE.....?

INCIDENCE IS NO OF NEW CASES ADDED TO A POPULATIOM IN A TIME PERIOD.....

INCIDENCE= NO OF NEW CASES ADDED TO A POPULATION/AT RISK INDIVISUAL

SO THE NO OF NEW CASES IS 1000

THE POPULATION AT RISK WUD BE= 1000000-10000=990000

AS 10000 PEOPLE R ALREADY HAVIN THE DS THEY WONT B AT RISK....

SO PEOPLE AT RISK WUD BE 990000.

HENCE INCIDENCE WUD B= 1000/990000

IT HAS NOTHIN TO DO WID DEATHS AS DEATH WUD AFFECT THE PREVLANCE NOT THE INCIDENCE......

THANX!

dr4jc · Credits: 4396 My Scrapbook

thanks for the clarification Bharat the answer should be C

ratnakar_potla · Credits: 5703 My Scrapbook My Reading List 2 Books

there again as i said thats a new concept of incidence.

I am sorry to say that atleast i dont accept with your logic of "at risk population".
The ones who had disease are also a part of the population and they were "at risk".

ref: park pg-55

sravya · Credits: 28740 My Scrapbook

yes! c is the answer!

but how come those having disease can be at risk, if they have already disease?

gudluck!

bye!

sprite · Credits: 762 My Scrapbook

c is the answer....

ppl with the dz are not at risk ...

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