4.

Changes in Distribution of HIV Sexual Risk Behavior Within Age Groups in 2 Probability Telephone Samples of Men Who Have Sex With Men: San Francisco, 1997 and 2002

	% of Participants, by Age Group
	UMHS 1997 (n = 915)				UMHS 2002 (n = 879)
Risk Category	18–29	30–39	40–49	≥50	18–29	30–39	40–49	≥50
No male sexual partners	16.3	7.3	13.4	30.6	3.0	7.4	10.6	26.3
No anal intercourse	13.4	22.9	27.4	35.5	7.6	12.2	17.1	28.7
Anal intercourse with 100% condom use	35.7	35.9	34.8	17.0	37.7	30.7	26.4	20.4
Unprotected anal intercourse, 100% HIV seroconcordant	25.1	24.1	14.8	9.7	40.0	32.5	28.8	14.5
Unprotected, serodiscordant anal intercourse, risk to the insertive partnera	5.7	4.3	5.9	3.0	5.1	10.0	7.9	5.2
Unprotected, serodiscordant anal intercourse, risk to the receptive partnerb	3.8	5.5	3.8	4.1	6.6	7.2	9.2	4.9

Note. UMHS = Urban Men’s Health Study. Respondents were classified into the highest risk category reported in the partner-by-partner assessment of up to 4 sexual partners in the past year. “Seroconcordant” means the respondent thought his partner had the same HIV infection status as himself; “serodiscordant” means that he thought they differed by HIV infection status.

^aUnprotected anal intercourse in which the insertive partner was HIV negative and the receptive partner was HIV positive or of unknown HIV status.

^bUnprotected anal intercourse in which the receptive partner was HIV negative and the insertive partner was HIV positive or of unknown HIV status