Hi.

I performed mutivariable logistic regression with quartile independent variable. (quartile of BMI)

4th quartile was set as a reference, and Odds ratios for each quartile are as below.

1st : 1.60 (1.39- 1.83)
2nd : 1.33 (1.16-1.52)
3rd : 1.14 (1.01-1.30)
4th : (Reference)

How can I test p for trend of Odds ratio ?

Thanks.