Does drinking coffee have an effect on low-birth weight?

Restricted to the smoking study participants, does drinking coffee have an effect on low birth weight?

Smokers

Cases	Controls

2×2 Table

	Cases	Controls
Coffee	20	8
No Coffee	5	2

Odds Ratio = 1.0

After stratifying the data on smoking and looking separately at smokers and non-smokers, it is evident that there is no effect of drinking on LBW.