Question

The following are data from a cohort study of the risk of stroke among male smokers and nonsmokers over the age of 65 years.

                              Stroke

                       Yes            No

Smoker           168          3,264    3,432

Non-smoker    102         4320    4,422

                       270          7,584   7,854

What is the relative risk for the association of smoking (versus no smoking) and stroke?

A.	(168 / 270) / (3,264 / 7,584) = 1.45
B.		(168 / 3,264) / (102 / 4,320) = 2.17
	C.	(168 / 3,432) / (102 / 4,422) = 2.13
	D.	(168 / 3,432) / (270 / 7, 854) = 1.42
	E.	None of the above.

Answer 1

The following are data from a cohort study of the risk of stroke among male smokers and nonsmokers over the age of 65 years.

A ) . (168 / 270) / (3,264 / 7,584)

= 1.45

  B ). (168 / 3,264) / (102 / 4,320)

= 2.17

C ). (168 / 3,432) / (102 / 4,422)

= 2.13

D ). (168 / 3,432) / (270 / 7, 854)

= 1.42

E ). None of the above

	Stroke
	Yes	No	Total
Smoker	168	3,264	3,432
Non-smoker	102	4,320	4,422
Total	270	7,584	7,854

Risk in smoking = 168/3432

Risk in non smoking = 102/4422

Relative risk   = Risk in smoking/ Risk in non smoking

= (168 / 3,432) / (102 / 4,422)

= 2.13