Question

In a cohort study of elderly patients (70 years of age and older), 1000 people with diabetes and 1500 people without diabetes were studied to evaluate whether diabetes is a risk factor for dementia. Participants were followed for 5 years. Of the diabetics, 380 developed dementia. Of the non-diabetics, 110 development dementia. Set up 2x2 table for this information and calculate the crude measure of association.

Answer 1

From 1000 people with Diabetes 380 developed dementia. From 1500 people without diabetes 110 development dementia

	Dementia	No mental illness
Diabetes	380 (a)	620 (b)
No Diabetes	110 (c)	1390 (d)

A crude measure of the association will be

(a $\div$ (a+b)) / (c $\div$ (c+d))

= 0.38 / 0.073

= 5.2

So, Risk ratio is 5.2 .

That means Diabetic people have 5 times more risk of developing Dementia than Non-Diabetic people