| |
Age <40 years
|
Age ≥40 years
|
Test for heterogeneity
|
|---|
|
Risk factor
|
Control subjects, n (%)
|
Cases, n (%)
|
OR (95 % CI)a
|
Control subjects, n (%)
|
Cases, n (%)
|
OR (95 % CI)a
|
χ2 test, df (p value)b
|
|---|
|
BMI, kg/m2
|
|
< 25.0
|
93 (41.9)
|
154 (49.2)
|
1.0
|
255 (40.0)
|
316 (44.3)
|
1.0
|
0.13, 2 (0.9)
|
|
25–29.9
|
58 (26.1)
|
71 (22.7)
|
0.72 (0.45–1.13)
|
184 (28.9)
|
181 (25.4)
|
0.87 (0.65–1.14)
| |
|
≥ 30.0
|
71 (32.0)
|
88 (28.1)
|
0.73 (0.47–1.13)
|
198 (31.1)
|
217 (30.4)
|
0.98 (0.74–1.29)
| |
|
Missing
| | | |
12
|
6
| | |
|
WHR
|
|
< 0.77
|
89 (41.4)
|
135 (44.3)
|
1.0
|
235 (36.8)
|
231 (32.4)
|
1.0
|
2.47, 2 (0.3)
|
|
0.77–0.83
|
68 (31.6)
|
98 (32.1)
|
0.94 (0.61–1.43)
|
209 (32.7)
|
245 (34.4)
|
1.42 (1.08–1.86)
| |
|
≥ 0.84
|
58 (27.0)
|
72 (23.6)
|
0.86 (0.54–1.36)
|
195 (30.5)
|
237 (33.2)
|
1.58 (1.18–2.11)
| |
|
Missing
|
7
|
8
| |
10
|
7
| | |
|
Parity
|
|
Nulliparous
|
49 (22.1)
|
70 (22.4)
|
1.0
|
76 (11.7)
|
106 (14.7)
|
1.0
|
3.55, 2 (0.2)
|
|
1–2 births
|
133 (59.9)
|
180 (57.5)
|
1.05 (0.67–1.63)
|
383 (59.0)
|
420 (58.3)
|
0.82 (0.58–1.14)
| |
|
≥ 3 births
|
40 (18.0)
|
63 (20.1)
|
1.29 (0.74–2.27)
|
190 (29.3)
|
194 (26.9)
|
0.81 (0.55–1.18)
| |
|
History of breastfeedingc
|
|
Never
|
77 (44.5)
|
145 (60.2)
|
1.0
|
343 (60.2)
|
370 (60.6)
|
1.0
|
9.01, 1 (0.003)
|
|
Ever
|
96 (55.5)
|
96 (39.8)
|
0.48 (0.31–0.75)
|
227 (39.8)
|
241 (39.4)
|
0.90 (0.70–1.16)
| |
|
Lifetime breastfeeding durationc
|
|
Never
|
86 (49.7)
|
148 (61.4)
|
1.0
|
346 (60.7)
|
378 (61.9)
|
1.0
|
6.36, 2 (0.04)
|
|
> 0–3 months
|
25 (14.5)
|
33 (13.7)
|
0.79 (0.43–1.45)
|
69 (12.1)
|
65 (10.6)
|
0.86 (0.58–1.25)
| |
|
≥ 4 months
|
62 (35.8)
|
60 (24.9)
|
0.50 (0.30–0.81)
|
155 (27.2)
|
168 (27.5)
|
0.87 (0.65–1.15)
| |
|
Time since last term pregnancyc
|
|
< 10 years
|
119 (68.8)
|
169 (70.1)
|
1.0
|
76 (13.3)
|
108 (17.7)
|
1.0
|
4.44, 2 (0.1)
|
|
10–19 years
|
50 (28.9)
|
66 (27.4)
|
1.02 (0.64–1.63)
|
302 (53.0)
|
283 (46.3)
|
0.71 (0.50–1.01)
| |
|
≥ 20 years
|
4 (2.3)
|
6 (2.5)
|
1.14 (0.30–4.27)
|
192 (33.7)
|
220 (36.0)
|
0.96 (0.64–1.43)
| |
|
Age at first live birthc
|
|
< 26 years
|
103 (59.5)
|
146 (60.6)
|
1.0
|
386 (67.7)
|
414 (67.8)
|
1.0
|
0.00, 1 (1.0)
|
|
≥ 26 years
|
70 (40.5)
|
95 (39.4)
|
1.03 (0.68–1.58)
|
184 (32.3)
|
197 (32.2)
|
0.93 (0.71–1.20)
| |
|
Age at last live birthc
|
|
< 30 years
|
102 (59.0)
|
148 (61.4)
|
1.0
|
344 (60.4)
|
362 (59.2)
|
1.0
|
0.01, 1 (0.9)
|
|
≥ 30 years
|
71 (41.0)
|
93 (38.6)
|
1.01 (0.67–1.54)
|
226 (35.6)
|
249 (40.8)
|
0.99 (0.78–1.26)
| |
|
Age at menarche
|
|
< 13 years
|
111 (50.2)
|
170 (54.3)
|
1.0
|
323 (49.8)
|
393 (54.6)
|
1.0
|
0.01, 1 (0.9)
|
|
≥ 13 years
|
110 (49.8)
|
143 (45.7)
|
0.85 (0.59–1.20)
|
326 (50.2)
|
327 (45.4)
|
0.83 (0.66–1.03)
| |
|
Missing
|
1
| | | | | | |
|
Oral contraceptive use
|
|
Never
|
33 (14.9)
|
36 (11.5)
|
1.0
|
112 (17.3)
|
125 (17.4)
|
1.0
|
0.67, 1 (0.4)
|
|
Ever
|
189 (85.1)
|
276 (88.5)
|
1.32 (0.78–2.22)
|
534 (82.7)
|
593 (82.6)
|
0.93 (0.70–1.25)
| |
|
Missing
| |
1
| |
3
|
2
| | |
-
BMI body mass index, WHR waist-to-hip ratio
-
aAdjusted for matching factors race and age
-
bLikelihood ratio tests were performed to assess age-related heterogeneity in risk factor associations by comparing the estimated log-likelihood of adjusted models with that of the adjusted model including a multiplicative interaction term for age and the corresponding risk factor (e.g., BMI × age). Statistically significant heterogeneity by age was defined with α = 0.1
-
cAmong parous women
