Table 1. Demographic characteristics among 52 selected participants stratified according to their sexual activity category at enrolment.

	Sexual activity category at enrolment
	no sexual activity	non-coital sexual activities onlya	penile-vaginal sex	Total
	N = 19	N = 19	N = 14	N = 52
	n (%)	n (%)	n (%)	n (%)	p value
Age [mean(±SD)]	[19.2 (1.1)]	[19.4 (1.1)]	[20.2 (1.2)]	[19.5 (1.2)]	0.043b
Smoker	0	1 (5.3)	1 (7.1)	2 (3.9)	0.728c
Practices douching	3 (15.8)	2 (10.5)	0	5 (9.6)	0.417c
Current OCP use	4 (21.1)	0	10 (71.4)	14 (26.9)	<0.001c
Ethnicity
Caucasian	7(36.8)	11 (57.9)	11 (78.6)	29 (55.8)	0.057d
Central & South-East Asiane	12 (63.2)	5 (26.3)	2 (14.3)	19 (36.5)	0.012d
Indian/Sri-Lankan	0	3 (15.8)	1 (7.1)	4 (7.7)	0.184d

All variables are self-reported. Key: SD = standard deviation, OCP = oral contraceptive pill.

^adigital or receptive oral sex

^banalysis of variance (ANOVA) of age by sexual activity category

^cFisher’s exact or Chi-squared analysis across all three sexual activity categories

^dChi-squared analysis comparing each ethnicity with the other two across all sexual activity categories

^ecomprises women of Chinese, Malay and Vietnamese ethnicities. The larger FUSS cohort consisted of N = 413 participants.