Table 1. Standardised incidence ratio (SIR) for NF1 female breast cancer by age group.

Age group	Observed	Expected	SIR	95% CI	P-value
<40 Years	9	0.63	14.25	6.51–27.04	<0.001
40–49 Years	6	2.31	2.60	0.95–5.65	0.0359
50–59 Years	8	3.75	2.13	0.92–4.20	0.0532
⩾60 years	8	4.30	1.86	0.80–3.66	0.1231
Total	31	11.00	2.82	1.92–4.00	<0.001

Abbreviations: CI=confidence interval; NF1=neurofibromatosis 1.