Question

Epidemiology

Please calculate the odds ratio for the following 2x2 tables and interpret the results to indicate if you think there may be confounding.

	Males	Females	Total
High Consumption	160	85	245
Low Consumption	129	193	322
	289	278	567

            Odds ratio =

            Interpretation =

Answer 1

let no of males with high consumption be represented by (a) = 160

No of females with high consumption = b= 85

No of individuals with high consumption = a/b = 160/85 = 1.88

No of males with low consumption= c= 129

No of females with low consumption = d = 193

No of individual with low consumption = c/d = 129/193= 0.66

Odd Ratio = No of individual with high consumption/ no of individual with low consumption

= 1.88/0.66 = 2.84

Interpretation:

Odd ratio = 1, means that exposure to high consuming individual does not affect the odds of low consuming individuals.

Odd ratio > 1, means that there is a higher odd of low consuming people with the exposure of high consuming indivdual

Odd ratio < 1 is associated with lower odds.