Table III.

Negative Binomial Regression Models of Discrimination (health and physical) and Substance Use (stimulant use, history of drug treatment, and history of alcohol treatment) on number of unprotected anal sex partners among MSM in Massachusetts.

	Incident Rate Ratio (IRR)	95%CI
Model 1
Health discrimination	0.05***	0.02–0.16
Stimulant use	0.03***	0.00–0.15
Health discrimination X Stimulant use	13.74***	2.20–85.61
Model 2
Health discrimination	0.04***	0.01–0.15
Drug treatment	0.02***	0.00–0.08
Health discrimination X Drug treatment	32.19***	5.69–182.00
Model 3
Health discrimination	0.05***	0.02–0.18
Alcohol treatment	0.02***	0.00–0.08
Health discrimination X Alcohol treatment	23.17***	4.23–126.84
Model 4
Physical discrimination	0.18***	0.09–0.39
Stimulant use	0.03***	0.00–0.17
Physical discrimination X Stimulant use	11.50*	1.62–81.14
Model 5
Physical discrimination	0.12***	0.04–0.36
Drug treatment	0.03***	0.01–0.10
Physical discrimination X Drug treatment	10.43**	2.45–44.33
Model 6
Physical discrimination	0.19***	0.08–0.46
Alcohol treatment	0.05***	0.02–0.20
Physical discrimination X Alcohol treatment	4.36*	1.12–16.93

^*p≤0.05;

^**p≤0.01;

^***p<0.001

Notably, the results did not change substantially when including age and race as covariates.