Table 3.
Relative risks (RRs) and 95% confidence intervals (CIs) for the association between genital talc use and ovarian cancer risk in the New England Case-Control Study (NECC) and the Nurses' Health Study (NHS)
| NECC† |
NHS† |
Pooled‡ |
|||||
|---|---|---|---|---|---|---|---|
| Cases (%) | Ctrls (%) | RR (95% CI) | Cases (%) | Ctrls (%) | RR (95% CI) | RR (95% CI) | |
| Total epithelial ovarian cancer: | |||||||
| N* | 1175 | 1202 | 210 | 600 | |||
| Regular genital talc use (>=once/week) | |||||||
| No | 859 (73.2) | 957 (79.7) | 1.00 (ref.) | 138 (70.8) | 414 (76.0) | 1.00 (ref.) | 1.00 (ref.) |
| Yes | 314 (26.8) | 244 (20.3) | 1.40 (1.15, 1.70) | 57 (29.2) | 131 (24.0) | 1.24 (0.83, 1.83) | 1.36 (1.14, 1.63) |
| Frequency of genital talc use | |||||||
| Never | 832 (70.9) | 916 (76.3) | 1.00 (ref.) | 120 (61.5) | 352 (64.6) | 1.00 (ref.) | 1.00 (ref.) |
| <once/week | 27 (2.3) | 41 (3.4) | 0.72 (0.43, 1.19) | 18 (9.2) | 62 (11.4) | 0.98 (0.54, 1.79) | 0.82 (0.55, 1.20) |
| 1-6 times/week | 123 (10.5) | 96 (8.0) | 1.33 (1.00, 1.79) | 22 (11.3) | 61 (11.2) | 1.01 (0.57, 1.79) | 1.26 (0.97, 1.63) |
| Daily | 191 (16.3) | 148 (12.3) | 1.41 (1.10, 1.79) | 35 (18.0) | 70 (12.8) | 1.44 (0.88, 2.37) | 1.41 (1.14, 1.76) |
| P-trend§ | 0.002 | 0.18 | <0.001 | ||||
| Serous invasive ovarian cancer: | |||||||
| N* | 450 | 1202 | 93 | 263 | |||
| Regular genital talc use (>=once/week) | |||||||
| No | 310 (69.0) | 957 (79.7) | 1.00 (ref.) | 60 (68.2) | 177 (73.8) | 1.00 (ref.) | 1.00 (ref.) |
| Yes | 139 (31.0) | 244 (20.3) | 1.62 (1.26, 2.09) | 28 (31.8) | 63 (26.3) | 1.48 (0.82, 2.68) | 1.60 (1.26, 2.02) |
| Frequency of genital talc use | |||||||
| Never | 299 (66.6) | 916 (76.3) | 1.00 (ref.) | 54 (61.4) | 151 (62.9) | 1.00 (ref.) | 1.00 (ref.) |
| <once/week | 11 (2.4) | 41 (3.4) | 0.65 (0.32, 1.33) | 6 (6.8) | 26 (10.8) | 0.79 (0.29, 2.11) | 0.70 (0.39, 1.24) |
| 1-6 times/week | 56 (12.5) | 96 (8.0) | 1.56 (1.08, 2.26) | 12 (13.6) | 25 (10.4) | 1.64 (0.71, 3.79) | 1.58 (1.12, 2.21) |
| Daily | 83 (18.5) | 148 (12.3) | 1.61 (1.18, 2.20) | 16 (18.2) | 38 (15.8) | 1.34 (0.65, 2.76) | 1.56 (1.17, 2.08) |
| P-trend§ | <0.001 | 0.29 | <0.001 | ||||
*
Frequencies do not add up to total N due to missing data on talc use
†
Unconditional (NECC) and conditional (NHS) logistic regression adjusted for age, study center (NECC only), duration of oral contraceptive use (months), parity (continuous), tubal ligation, body mass index (kg/m2, continuous), and duration of postmenopausal hormone use (months)
‡
P-values for tests for heterogeneity comparing the NECC and NHS results were all >0.38
§
Weighted by the midpoint of each category of genital talc use frequency and calculated using the Wald test