Table 1. Socio-demographic characteristics.

		n	%
Current residence	Tokyo	883	53.4
	Greater Tokyo	553	33.4
	Another prefecture	209	12.6
	Another country	8	0.5
	Total	1653	100.0
Birthplace	Japan	1593	96.3
	Other	62	3.7
	Total	1655	100.0
Age	18–25	319	19.4
	26–35	550	33.4
	36–45	507	30.8
	46+	270	16.4
	Total	1646	100.0
Gender	Male	1641	99.2
	Other	14	0.8
	Total	1655	100.0
Marital status	No	1582	95.6
	Yes	72	4.4
	Total	1654	100.0
Occupation	Full-time	1133	68.5
	Part-time	185	11.2
	Student	168	10.2
	Self-employed	73	4.4
	Freelance	16	1.0
	Unemployed	69	4.2
	Other	9	0.5
	Total	1653	100.0
Education	High school or less	421	25.4
	Two-year technical school	274	16.5
	University	800	48.3
	M.A.	135	8.2
	PhD	26	1.6
	Total	1656	100.0
Intercourse partner sex	Men	1488	91.1
	Men and women	146	8.9
	Total	1634	100
Sexuality	Homosexual	1408	85.1
	Bisexual	233	14.1
	Other	14	0.8
	Total	1655	100
Health	Healthy	1056	63.9
	Fair or poor health	598	36.1
	Total	1654	100