Table 1. Characteristics of participants.

Variable	Covariate	Observation/Missing	Mean /proportion	95% CI	RDS estimate	95% CI
Age		121/2	32.06	[29.88 34.24]	33.27	[30.19 36.36]
Nationality	Swedish	121/2	0.86	[0.80 0.92]	0.81	[0.72 0.90]
County of residence	Stockholm county	121/2	0.25	[0.17 0.32]	0.22	[0.11 0.33]
Education	Tertiary	121/2	0.28	[0.20 0.36]	0.27	[0.15 0.38]
	Secondary		0.51	[0.42 0.60]	0.44	[0.32 0.57]
	Vocational training		0.12	[0.07 0.18]	0.11	[0.03 0.19]
	Primary (grade 1–9)		0.08	[0.0 0.14]	0.19	[0.00 0.27]
Occupation	Employed including students and retired respondents	121/2	0.79	[0.71 0.86]	0.82	[0.72 0.93]
Sexual orientation	Homosexual	121/2	0.75	[0.68 0.83]	0.78	[0.67 0.89]
	Bisexual		0.23	[0.16 0.31]	0.29	[0.18 0.40]
	Heterosexual		0.03	[0.00 0.06]	0.02	[0.00 0.07]
	Asexual		0.02	[0 0.04]	0.00	[0 0.04]
	Don’t know		0.03	[0 0.06]	0.02	[0 0.06]
Network size	Reported number of MSM possible to invite	105/18	31.03	[11.49 50.57]
Web-community profile	1 profile	116/7	0.79	[0.72 0.87]	0.81	[0.71 0.91]
	2 profiles		0.09	[0.04 0.15]	0.09	[0.01 0.16]
	≥3 profiles		0.11	[0.05 0.17]	0.10	[0.02 0.18]
Level of Web-community membership	Highest level	116/7	0.38	[0.29 0.47]	0.33	[0.21 0.46]