Table 1. Characteristics of participants in the Shanghai Women's Health Study (SWHS), by epithelial ovarian cancer (EOC) status.
| Characteristics | EOC casesa | Non-EOC cases | P-valueb |
|---|---|---|---|
| Participants (N) |
152 |
70 106 |
— |
| Person-years |
891.45 |
760 497.86 |
— |
| Age at interview |
52.91±8.75 |
52.46±9.07 |
0.547 |
| Age at menarche |
14.91±1.71 |
14.94±1.74 |
0.834 |
| Postmenopausal |
78 (51.32%) |
33 431 (47.70%) |
0.372 |
| Age at menopausec |
50.22±3.21 |
49.23±3.71 |
0.022 |
| Hormone replacement therapy |
2 (1.32%) |
1153 (1.64%) |
0.750 |
| Parous |
145 (95.39%) |
67 885 (96.83%) |
0.313 |
| Total years of menstruation |
30.28±4.76 |
29.43±4.95 |
0.036 |
| Ever oral contraceptive use |
31 (20.39%) |
14 327 (20.44%) |
0.990 |
| Irregular ovulatory cycles |
4 (2.63%) |
4692 (6.69%) |
0.045 |
| Education (college and above) |
17 (11.18%) |
9319 (13.30%) |
0.444 |
| Ever drank regularly |
5 (3.29%) |
1585 (2.26%) |
0.394 |
| Ever smoked regularly |
9 (5.92%) |
1943 (2.77%) |
0.018 |
| Passive smoke exposure |
126 (82.89%) |
56 417 (80.47%) |
0.452 |
| Ever drank tea |
47 (30.92%) |
20 947 (29.88%) |
0.779 |
| Family history of any cancer |
46 (30.26%) |
18 452 (26.32%) |
0.270 |
| Family history of breast or ovarian cancer |
3 (1.97%) |
1472 (2.10%) |
0.914 |
| History of fibroadenomas |
4 (2.63%) |
2307 (3.29%) |
0.649 |
| Occupation (manual workers) |
77 (50.66%) |
35 539 (50.69%) |
0.993 |
| Family income (high) |
50 (32.89%) |
23 379 (33.35%) |
0.906 |
| Regular physical activity |
55 (36.18%) |
24 390 (34.79%) |
0.719 |
| Physical activity unitsd |
1.76±1.71 |
1.94±2.10 |
0.520 |
| Energy intake | 1700.20±386.10 | 1675.90±405.80 | 0.461 |
Abbreviation: EOC=epithelial ovarian cancer.
a
Incident EOC cases diagnosed during follow-up.
b
Continuous variables: mean values±standard deviation, P-values from t-tests; categorical variables: numbers and percentages, P-values from χ2 test and Fisher's exact test; P-values in bold denote significance at ⩽0.05.
c
Age at natural menopause for postmenopausal women; not including 2106 women with surgical or other non-natural causes of menopause.
d
Units of physical activity defined as MET-h day−1year−1; only available for participants with regular physical activity.