Retrospective Study
Copyright ©2014 Baishideng Publishing Group Inc.
World J Clin Oncol. Dec 10, 2014; 5(5): 1097-1106
Published online Dec 10, 2014. doi: 10.5306/wjco.v5.i5.1097
Table 2 Associated risk factors for breast cancer development in the total patient population (n = 7152)
< 40 yr (n = 1008) n (%)40 yr (n = 6144) n (%)P value
Family history of breast cancer
Yes178(17.7)891(14.5)χ2 = 6.788, aP = 0.010
No830(82.3)5 253(85.5)
Lifestyle-related risk factors
Lack of exercise (< 3h/wk)
Yes861(85.4)4 497(73.2)χ2 = 68.848, bP < 0.001
No147(14.6)1 647(26.8)
High level of stress (> 50% of time)
Yes465(46.1)2 179(35.5)χ2 = 42.272, aP < 0.001
No543(53.9)3 965(64.5)
Being overweight/obese (BMI ≥ 23.0)
Yes241(23.9)2 344(38.2)χ2 = 76.104, bP < 0.001
No767(76.1)3 800(61.8)
Diet rich in meat/dairy products
Yes204(20.2)791(12.9)χ2 = 39.205, bP < 0.001
No804(79.8)5 353(87.1)
Frequently night shifts
Yes81(11.4)285(9.3)χ2 = 2.958, P = 0.091
No632(88.6)2 796(90.7)
Alcohol drinking habit
Yes77(7.7)316(5.2)χ2 = 10.008, bP = 0.002
No925(92.3)5 747(94.8)
Hormone-related risk factors
Breastfeeding
Yes226(46.3)1 933(40.9)χ2 = 5.249, aP = 0.023
No262(53.7)2 788(59.1)
Nulliparity
Yes381(43.3)1 042(17.8)χ2 = 297.601, bP < 0.001
No499(56.7)4 805(82.2)
First live birth age after 35
Yes21(4.3)238(5.1)χ2 = 0.630, P = 0.514
No469(95.7)4 420(94.9)
Early menarche (< 12 yr old)
Yes197(20.7)759(13.2)χ2 = 37.243, bP < 0.001
No755(79.3)4 982(86.8)
Use of hormone replacement therapy
Yes5(8.1)376(11.7)χ2 = 0.778, P = 0.546
No57(91.9)2 841(88.3)