Table 5.

Multivariable model for younger group using stepwise regression with AIC criterion*

Risk factor		Beta	Odds ratio	95% CI (Lower -Upper)			p value
	(Intercept)	−0.64	0.53	0.35	-	0.8		0.002	***
Palpable lump							0		***
	No corresponding palpable mass	0	1(referent)
	Missing	−0.68	0.51	0.16	-	1.6		0.246
	Corresponding palpable mass	1.21	3.36	1.79	-	6.32		0	***
Principal mammography finding							0		***
	Calcifications or Single dilated duct	0	1(referent)
	Architectural distortion	1.95	7.05	0.75	-	65.98		0.087	*
	Associated calcifications	1.58	4.85	1.87	-	12.55		0.001	***
	Missing	1.02	2.76	1.34	-	5.7		0.006	***
	Asymmetry or Focal asymmetry	1.86	6.41	1.26	-	32.64		0.025	**
	Mass	2.74	15.51	4.97	-	48.35		0	***
	Developing asymmetry	16.5	Inf	0	-	Inf		0.997
Architectural distortion							0.063		*
	Not present	0	1(referent)
	Present	1.78	5.91	0.67	-	52.13		0.11
Mass shape							0.09		*
	None	0	1(referent)
	Irregular	15.83	Inf	0	-	Inf		0.986
	Lobular or Oval	0.09	1.1	0.23	-	5.21		0.787
	Round	−19.53	0	0	-	Inf		0.996
Mass size							0.047		*
	None	0	1(referent)
	20-Oct	−0.97	0.38	0.03	-	4.61		0.447
	20-50	1.7	5.47	1.17	-	25.69		0.031	**
	<10	−0.58	0.56	0.19	-	1.63		0.287
	> = 50	−0.58	0.56	0.14	-	2.25		0.413

The model is presented in the order of inclusion into the model.

*Asterisks denote the level of significance such that: *** p-value < 0.001; **p-value < 0.05, and * p-value <0.1.

“Inf” (short for infinity) is inserted at places where the data for the corresponding variable is sparsely populated and produces a very high and unstable odds ratio.