|
Group 1 (%)a |
Group 2
(%)b |
|
Group 1 (%)a |
Group 2 (%)b |
Number of participants |
5,422 (100.0) |
2,467 (100.0) |
|
5,422 (100.0) |
2,467 (100.0) |
Region |
|
|
|
|
|
Anhui |
1,317 (24.3) |
450 (18.2) |
|
– |
– |
Beijing |
261 (4.8) |
170 (6.9) |
|
– |
– |
Fujian |
853 (15.7) |
130 (5.3) |
|
– |
– |
Hebei |
1,638 (30.2) |
897 (36.4) |
|
– |
– |
Heilongjiang |
405 (7.5) |
137 (5.6) |
|
– |
– |
Nei Mongo |
397 (7.3) |
168 (6.8) |
|
– |
– |
Zhejiang |
551 (10.2) |
515 (20.9) |
|
– |
– |
P value
|
<.01 |
<.01 |
|
– |
– |
Agec, years |
|
|
|
|
|
20–24 |
2,297 (49.5) |
856 (41.2) |
|
1,150 (30.2) |
440
(26.0) |
25–29 |
1,617 (34.8) |
704 (33.9) |
|
1,570 (41.3) |
616
(36.4) |
30–34 |
463 (10.0) |
179 (8.6) |
|
632 (16.6) |
226
(13.4) |
35–39 |
234 (5.0) |
315 (15.2) |
|
370 (9.7) |
347
(20.5) |
≥40 |
33 (0.7) |
24 (1.2) |
|
83 (2.2) |
62 (3.7) |
Mean (SD) |
25.6 (4.3) |
26.4 (4.9) |
|
27.6 (4.8) |
28.5
(5.2) |
P value
|
<.01 |
<.01 |
|
<.01 |
<.01 |
Ethnicity |
|
|
|
|
|
Han ethnic group |
5,259 (97.4) |
2,379 (97.3) |
|
5,244 (98.0) |
2,390
(98.3) |
Minoritiesd
|
139 (2.6) |
65 (2.7) |
|
110 (2.1) |
41
(1.7) |
P value
|
NS |
NS |
|
NS |
NS |
Current BMI, kg/m2 |
|
|
|
|
|
<18.50 |
271 (5.0) |
166 (6.8) |
|
96 (1.8) |
49
(2.0) |
18.50–23.99 |
3,781 (70.3) |
1,738 (71.0) |
|
3,873 (72.4) |
1,645
(68.0) |
24.00–27.99 |
1,187 (22.1) |
481 (19.7) |
|
1,270 (23.7) |
676
(28.0) |
≥28.00 |
136 (2.5) |
63 (2.6) |
|
112 (2.1) |
48 (2.0) |
Mean (SD) |
22.4 (2.5) |
22.1 (2.6) |
|
22.7 (2.2) |
23.0
(2.2) |
P value
|
<.01 |
<.01 |
|
<.01 |
<.01 |
Education |
|
|
|
|
|
Primary school and below |
312 (5.8) |
188 (7.6) |
|
228 (4.3) |
155
(6.4) |
Middle school |
3,307 (61.1) |
1,527 (62.0) |
|
3,255 (60.7) |
1,519
(62.3) |
High school |
947 (17.5) |
396 (16.1) |
|
968 (18.1) |
389
(15.9) |
College and beyond |
844 (15.6) |
352 (14.3) |
|
908 (16.9) |
377
(15.5) |
P value
|
<.01 |
<.01 |
|
<.01 |
<.01 |
Occupation |
|
|
|
|
|
Clerk |
346 (6.4) |
157 (6.4) |
|
382 (7.1) |
183 (7.5) |
Professional worker |
258 (4.8) |
198 (8.1) |
|
720 (13.4) |
312
(12.8) |
Service worker |
553 (10.2) |
438 (17.8) |
|
1,063 (19.7) |
407
(16.6) |
Agricultural and related worker |
1,491 (27.6) |
688 (28.0) |
|
1,591
(29.6) |
750 (30.6) |
Factory worker |
111 (2.1) |
92 (3.7) |
|
743 (13.8) |
308
(12.6) |
Unemployed |
2,408 (44.5) |
599 (24.4) |
|
46 (0.9) |
33
(1.4) |
Others or not stated |
243 (4.5) |
285 (11.6) |
|
839 (15.6) |
455
(18.6) |
P value
|
<.01 |
<.01 |
|
<.01 |
<.01 |
Annual household income, yuan |
|
|
|
|
|
<10,000 |
3,214 (60.0) |
1,298 (53.2) |
|
– |
– |
10,000–19,999 |
1,288 (24.1) |
602 (24.7) |
|
– |
– |
>20,000 |
853 (15.9) |
538 (22.1) |
|
– |
– |
P value
|
<.01 |
<.01 |
|
– |
– |
Toxic exposuree |
|
|
|
|
|
Yes |
73 (1.4) |
90 (3.8) |
|
163 (3.3) |
131 (5.7) |
No |
5,176 (98.61) |
2,291 (96.2) |
|
4,860 (96.8) |
2,169
(94.3) |
P value
|
<.01 |
<.01 |
|
<.01 |
<.01 |
Smoking |
|
|
|
|
|
Yes |
18 (0.3) |
13 (0.5) |
|
2,302 (42.7) |
1,125 (45.7) |
Nof
|
5,399 (99.7) |
2,449 (99.5) |
|
3,093 (57.3) |
1,336 (54.3) |
P value
|
NS |
NS |
|
.01 |
.01 |
Drinking |
|
|
|
|
|
Yes |
88 (1.6) |
40 (1.6) |
|
2,492 (46.1) |
1,138 (46.3) |
Nog
|
5,324 (98.4) |
2,417 (98.4) |
|
2,914 (53.9) |
1,320 (53.7) |
P value
|
NS |
NS |
|
NS |
NS |
Physical exercise |
|
|
|
|
|
Occasionally |
4,551 (84.7) |
1,992 (82.0) |
|
– |
– |
2–3 times a month |
632 (11.8) |
344 (14.2) |
|
– |
– |
At least once a week |
193 (3.6) |
94 (3.9) |
|
– |
– |
P value
|
<.01 |
<.01 |
|
– |
– |
Duration of cohabitation,
yearsh |
Duration of cohabitation,
yearsh |
Duration of cohabitation,
yearsh |
Duration of cohabitation,
yearsh |
Duration of cohabitation,
yearsh |
Duration of cohabitation,
yearsh |
Mean (SD) |
3.7 (3.7) |
6.1 (4.8) |
|
– |
– |
Menstrual cycle interval
(day)i |
Menstrual cycle interval
(day)i |
Menstrual cycle interval
(day)i |
Menstrual cycle interval
(day)i |
Menstrual cycle interval
(day)i |
Menstrual cycle interval
(day)i |
≤23 |
375 (7.0) |
213 (8.9) |
|
– |
– |
24–35 |
4,798 (89.7) |
1,953 (81.4) |
|
– |
– |
>35 |
155 (2.9) |
215 (8.9) |
|
– |
– |
Others or not stated |
23 (0.4) |
19 (0.8) |
|
|
|
P value
|
<.01 |
<.01 |
|
– |
– |
History of abnormal pregnancy |
History of abnormal
pregnancy |
History of abnormal pregnancy |
History of
abnormal pregnancy |
History of abnormal pregnancy |
History of abnormal pregnancy |
No |
4,851 (89.5) |
2,120 (85.9) |
|
– |
– |
Yes |
571 (10.5) |
347 (14.1) |
|
– |
– |
P value
|
<.01 |
<.01 |
|
– |
– |
Parity |
|
|
|
|
|
Nullipara |
3,629 (66.9) |
1,751 (71.0) |
|
– |
– |
Multipara |
1,793 (33.1) |
716 (29.0) |
|
– |
– |
P value
|
<.01 |
<.01 |
|
– |
– |