Table 4

Sociodemographic, anthropometric and attitudinal characteristics associated with lifetime and past year use of sexual services among male NInJaS respondents aged 20–49 years (multivariate ORs including all independent variables in a single model)

Variable	Category	Lifetime aOR (95% CI)	Lifetime P value	Past year* aOR (95% CI)	Past year P value
Sociodemographics
Age		1.04 (1.03–1.05)*	<0.001	0.99 (0.97–1.01)	0.214
Marital status	Married	Ref.		Ref.
	Never married	0.74 (0.61–0.90)*	0.003	1.38 (0.98–1.93)	0.061
	Previously married	1.60 (1.10–2.33)*	0.014	1.73 (0.96–3.13)	0.07
Relationship status	Married	Ref.		Ref.
	Cohabiting	2.14 (1.26–3.66)*	0.005	2.08 (1.13–3.84)*	0.019
	In a relationship	1.24 (0.92–1.67)	0.151	0.96 (0.61–1.51)	0.854
	Not in a relationship	–		–
Sexual orientation	Heterosexual	Ref.		Ref.
	Bisexual	2.46 (1.55–3.90)*	<0.001	2.44 (1.39–4.29)*	0.002
	Homosexual	0.76 (0.46–1.28)	0.309	0.39 (0.14–1.06)	0.065
	Asexual	1.20 (0.86–1.69)	0.286	0.68 (0.34–1.37)	0.285
	Other	0.64 (0.14–2.95)	0.568	6.11 (1.57–23.76)*	0.009
Occupational status	Full-time	Ref.		Ref.
	Part-time	0.70 (0.52–0.95)*	0.023	0.67 (0.38–1.20)	0.182
	Self-employed	0.85 (0.62–1.18)	0.342	0.77 (0.42–1.41)	0.396
	Student	0.59 (0.33–1.05)	0.072	0.64 (0.24–1.71)	0.374
	House-husband	0.46 (0.14–1.53)	0.205	2.40 (0.50–11.39)	0.272
	Unemployed	0.50 (0.33–0.76)*	0.001	0.24 (0.09–0.63)*	0.004
Income	<100	Ref.		Ref.
in ¥10 000 s	100–299	1.20 (0.83–1.74)	0.32	1.45 (0.70–3.00)	0.321
	300–499	2.43 (1.66–3.57)*	<0.001	2.08 (0.96–4.50)	0.063
	500–799	3.45 (2.28–5.20)*	<0.001	2.50 (1.11–5.66)*	0.028
	>800	2.75 (1.73–4.35)*	<0.001	2.15 (0.88–5.28)	0.093
Education	High school or less	Ref.		Ref.
	Trade/vocational school or short college	0.88 (0.67–1.14)	0.337	0.72 (0.45–1.16)	0.181
	Undergraduate studies	0.96 (0.78–1.17)	0.675	1.04 (0.76–1.43)	0.803
	Graduate studies	0.62 (0.44–0.85)*	0.004	0.97 (0.57–1.63)	0.897
Region of residence	Hokkaido & Tohoku	Ref.		Ref.
	Kanto	0.83 (0.63–1.10)	0.197	1.22 (0.75–1.99)	0.429
	Chubu	0.89 (0.65–1.22)	0.466	1.14 (0.66–1.96)	0.647
	Kansai	0.87 (0.64–1.19)	0.385	1.28 (0.75–2.20)	0.362
	Chugoku & Shikoku	0.74 (0.50–1.10)	0.137	0.77 (0.38–1.57)	0.471
	Kyushu & Okinawa	1.25 (0.86–1.81)	0.243	1.25 (0.65–2.41)	0.498
Urbanity of residence	Within Tokyo's 23 wards or prefectural capital	Ref.		Ref.
	In Tokyo but outside of the 23 wards	0.89 (0.60–1.32)	0.555	1.45 (0.80–2.64)	0.222
	Cities other than prefectural capitals (population>5 00 000)	0.98 (0.76–1.27)	0.885	1.03 (0.68–1.55)	0.894
	Cities other than prefectural capitals (population 3 00 000–4 99 999)	1.14 (0.87–1.49)	0.329	0.95 (0.61–1.50)	0.839
	Cities other than prefectural capitals (population<3 00 000)	0.87 (0.70–1.08)	0.204	1.04 (0.73–1.48)	0.831
	Village or town	1.05 (0.77–1.44)	0.753	1.13 (0.68–1.88)	0.632
Anthropometrics
Height		0.97 (0.94–1.00)*	0.021	0.95 (0.92–0.99)*	0.021
Weight		1.03 (1.00–1.06)*	0.024	1.05 (1.00–1.10)*	0.038
BMI		0.94 (0.87–1.01)	0.086	0.92 (0.82–1.04)	0.166
How would you describe your attractiveness?	Above average	Ref.		Ref.
	About average	0.50 (0.37–0.67)*	<0.001	1.28 (0.81–2.01)	0.286
	Below average	0.44 (0.32–0.60)*	<0.001	1.03 (0.63–1.70)	0.908
Attitudes
“I am satisfied with my sex life.”	Strongly agree	1.06 (0.67–1.68)	0.81	0.50 (0.25–0.98)*	0.043
	Agree	1.21 (0.97–1.52)	0.094	0.99 (0.69–1.42)	0.949
	Neutral	Ref.		Ref.
	Disagree	1.05 (0.81–1.36)	0.717	1.03 (0.70–1.52)	0.88
	Strongly disagree	0.95 (0.70–1.27)	0.707	0.71 (0.45–1.13)	0.153
Would you like to change your frequency of sexual intercourse?	Yes, I would like to increase it a lot	2.22 (1.64–3.01)*	<0.001	1.92 (1.23–3.00)*	0.004
	Yes, I would like to increase it a little	1.52 (1.22–1.89)*	<0.001	1.50 (1.05–2.15)*	0.026
	No	Ref.		Ref.
	Yes, I would like to decrease It a little	1.47 (0.81–2.69)	0.207	1.38 (0.57–3.33)	0.472
	Yes, I would like to decrease it a lot	0.68 (0.39–1.20)	0.18	1.72 (0.73–4.06)	0.213
How important is sex to you?	Very important	1.59 (1.18–2.13)*	0.002	2.16 (1.36–3.44)*	0.001
	Somewhat important	1.51 (1.22–1.88)*	<0.001	1.26 (0.87–1.85)	0.226
	Neither important nor unimportant	Ref.		Ref.
	Not very important	0.92 (0.68–1.26)	0.607	0.65 (0.32–1.31)	0.231
	Not important at all	0.70 (0.47–1.06)	0.095	0.96 (0.48–1.89)	0.896

*P<0.05.
– denotes unable to calculate.
*The following two questions were included In the NInJaS survey: (1) How many sexual partners have you had in the last year, including CSWs? (2) How many sexual partners have you had in the last year, excluding CSWs? Use of CSW services in the past year was defined by taking the difference between these two answers and obtaining a value of 1 or greater.
aOR, adjusted OR; BMI, body mass index; CSW, commercial sex work; NInJaS, National Inventory of Japanese Sexual Behavior.