Development and validation of a risk prediction model for premenopausal breast cancer in 19 cohorts

Breast Cancer Research

Table 3 Beta coefficients and hazard ratios (HR) and 95% confidence intervals (CI) for the PBCCG risk model for premenopausal breast cancer

	Full Dataset^a		Subset with complete covariate data^b
Variable	Beta	HR (95% CI)^c	HR (95% CI)^d
Age at menarche (per year)	−0.046	0.96 (0.94–0.97)	0.95 (0.93–0.98)
Parity (per child)	−0.131	0.88 (0.84–0.91)	0.89 (0.87–0.92)
Height (cm)^e	0.110	1.12 (1.03–1.21)	1.17 (1.11–1.23)
BMI (kg/m²)^f	−0.124	0.88 (0.82–0.95)	0.92 (0.88–0.95)
BMI age 18–24 (kg/m2)^f	−0.079	0.92 (0.85–1.01)	0.89 (0.83–0.96)
History of BBD	0.440	1.55 (1.45–1.66)	1.55 (1.45–1.67)
Family history of BC	0.541	1.72 (1.59–1.85)	1.72 (1.58–1.87)

BBD Benign breast disease, BMI Body mass index, PBCCG Premenopausal Breast Cancer Collaborative Group
^aEstimates from training dataset, N = 522,700 Cases = 6,392
^bCohorts include those with no model variables missing by design: BCN Generations Study, E3 N, Nurses’ Health Study, Nurses’ Health Study II, The Sister Study, Women’s Lifestyle and Health Study, Shanghai Women’s Health Study. Estimates from training data, N = 284,149, Cases = 3,777
^cBeta estimates calculated following generalized meta-analysis with random effects model, mutually adjusted for all listed variables
^dBeta estimates calculated directly from Cox PH model results among complete case dataset, mutually adjusted for all listed variables
^eEstimated per 10 cm
^fEstimated per 5 kg/m2

ISSN: 1465-542X