Table 1. Demographics of 54 postmenopausal women without breast cancer, by mammographic density*.

	Low Density (n = 23)	High Density (n = 31)	p-value*
Mean Age(SD)	61.17 (3.7)	61.8 (3.6)	0.48
White Non—Hispanic %	91%	81%	0.35
Attended College	95%	96%	0.88
Mean BMI	29.64 (4.9)	26.18 (5.73)	0.01
Normal	17%	52%	0.01
Overweight	35%	35%
Obese	48%	13%
Ever Smoked 100 Cigarettes	54%	41%	0.36
Currently Drink Alcohol	77%	77%	0.99
Vigorous Physical Activity
No vigorous physical activity	27%	29%	0.38
< 2 hours of vigorous activity/week	41%	55%
> 2 hours of vigorous activity /week	32%	16%
Moderate Physical Activity
No moderate physical activity	14%	6%	0.65
< 2 hours of moderate activity/week	36%	36%
> 2 hours of moderate activity /week	50%	58%
Gail score
Median 5- year risk	1.8 (0.17)	1.7 (0.19)	0.55
Median lifetime risk	8.7 (0.69)	7.9 (0.84)	0.33
History of Hormone Replacement Therapy	36%	56%	0.18
History of Family Cancer	21%	16%
Reproductive information	N = 22	N = 27
Median age at menarche, SE	13 (0.32)	13 (0.31)	0.31
Median age at menopause SE	52 (1.4)	50 (1.8)	0.12
Median years since menopause, SE	9 (1.6)	11 (1.9)	0.15
Reported parity Information	N = 19	N = 23
At least one live birth	74%	87%	0.27

*Symmetrically distributed continuous variables such as age were assessed by Student’s T-Test. Non–symmetrically distributed continuous variables including age at menopause, age at menarche, years since menopause, 5-year and lifetime risk of breast cancer (Gail risk score) were assessed using Wilcoxon rank sum test. Categorical variables were analyzed using chi–square analysis (race, college attendance, body mass index categories, ever smoked, current alcohol use, history of family cancer, previous use of hormone replacement therapy, at least one live birth, and moderate/vigorous physical activity).