Table 1.

Demographic parameters of the high-risk and low-risk cohorts

	Low-risk cohort (n=359)	High-risk cohort (n=400)
	N (%)	N (%)
Gender (% female)	189 (52.6)	272* (68)
Age (mean)	15.5	15.5
Population group
Black South African	17 (4.7)	400* (100)
White South African	319* (88.8)	0 (0)
Mixed South African	23* (6.4)	0 (0)

*P<0.001.