# Thread: calculation of relative risk.

1. ## calculation of relative risk.

..........................Smokers...................Non- Smokers
Iron Exopsure.......+..........-...................+..........-

Lung cancer.........111.......28..................11........10
No Lung cancer......99.......222.............. 159........190

1)Risk of lung cancer related to iron wxposure. Whats its best estimate?

I say relative risk. or is it the odds ratio?

2) Calculate this risk.
Do i consider the non-smoker table or do i set a new table with the disease and the exposure being iron exposure regardless of smoking?

3) Does the risk of lung cancer related to iron exposure differ in the presence of smoking? Explain why using numbers.

I would highly appreciate your help. thanks a lot.

2. ## Re: calculation of relative risk.

Hey Bahaa123.

For 1) you should use relative risk. Although it can be approximated by the odds ratio in special circumstances, it is not the same as relative risk in general.

Do you know the formula for relative risk?

3. ## Re: calculation of relative risk.

Here is the formula that I used http://en.wikipedia.org/wiki/Relative_risk for your first question

Spoiler:

For your second question, I guess you don't need to take account for the effect of smoking yet. And for the third question, it is actually just doing the same thing but with separate cases of smokers and non-smokers.