Breast Density and Breast Cancer Incidence in the Lebanese Population: Results from a Retrospective Multicenter Study

Table 2

(a) Distribution of breast density in Lebanese women (,049).

Age (years)	Breast density category
	I		II		III		IV
	<30	0	0.0%	4	30.8%	4	30.8%	5	38.5%
30–39	4	3.6%	22	20.0%	72	65.5%	12	10.9%
40–49	8	2.3%	87	24.8%	216	61.5%	40	11.4%
50–59	30	10.3%	128	43.8%	124	42.5%	10	3.4%
60–69	33	19.0%	97	55.7%	41	23.6%	3	1.7%
>70	27	24.8%	55	50.5%	24	22.0%	3	2.8%
Total	102	9.7%	393	37.5%	481	45.9%	73	7.0%

(b) Mean age and parity in different breast density groups (,049).

	Breast density		Mean	Standard deviation	Minimum	Maximum
Age	I	102	62.18	11.43	33.00	84.00	<0.001
	II	393	56.41	11.32	28.00	82.00
	III	481	48.52	10.16	18.00	89.00
	IV	73	45.34	10.96	25.00	82.00
	Total	1,049	52.59	11.90	18.00	89.00
Parity	I	99	2.93	1.85	0.00	8.00	<0.001
	II	365	2.58	1.64	0.00	9.00
	III	447	2.00	1.44	0.00	7.00
	IV	62	1.66	1.44	0.00	6.00
	Total	973	2.29	1.60	0.00	9.00

level set at 5%. ANOVA test shows that the breast density decreased when age ( value < 0.001) and parity ( value < 0.001) increase.