Table 2.

Prevalence of rheumatic heart disease in siblings vs. background population children.

	Borderline RHD		Definite RHD		Total RHD (Borderline + Definite)
Siblings	9/133	68 per 1000 95% CI 36–124 per 1000	3/133	23 per 1000 95% CI 8–64 per 1000	12/133	90 per 1000 95% CI 45–143 per 1000
NZ children (6)	90/3634	25 per 1000 95% CI 20–30 per 1000	40/3634	11 per 1000 95% CI 8–15 per 1000	130/3634	36 per 1000 95% CI 30–42 per 1000
p-value	0.002		0.218		0.001