Table 1.
Summary risk estimates of the association between menarcheal age and ovarian cancer risk
| No. of studies | Summary RR (95% CI) | Q Statistic | I-square Value (%) | Ph* | Ph** | Study Reference | |
|---|---|---|---|---|---|---|---|
| Overall | 25 | 0.85 (0.75–0.97) | 39.81 | 42.2 | 0.016 | — | 8–12, 22–24, 26–31, 33–43 |
| Subgroup analyses | 0.146 | ||||||
| High quality studies (scores ≥7) | 18 | 0.83 (0.76–0.91) | 21.70 | 26.3 | 0.153 | 8–10, 22, 26–31, 33–36, 38–40, 42 | |
| Study Design | 0.673 | ||||||
| Cohort studies | 5 | 0.89 (0.76–1.03) | 0.56 | 0 | 0.968 | 8, 9, 26–28 | |
| Case-control studies | 20 | 0.84 (0.70–0.99) | 38.92 | 53.7 | 0.003 | 10–12, 22–24, 29–31, 33–43 | |
| Exposure Assessment | 0.946 | ||||||
| Trained interviewer | 15 | 0.81 (0.68–0.97) | 24.49 | 42.8 | 0.040 | 10, 11, 22–24, 33–36, 38–43 | |
| Self-administered questionnaire | 8 | 0.87 (0.77–0.99) | 7.48 | 19.8 | 0.279 | 8, 9, 26–31 | |
| Type of Control Subjects | 0.327 | ||||||
| Population based | 7 | 0.79 (0.60–1.04) | 12.68 | 59.9 | 0.029 | 10, 22, 30, 31, 33, 36, 40 | |
| Hospital based | 12 | 0.91 (0.70–1.19) | 24.99 | 56.0 | 0.009 | 11, 12, 23, 24, 29, 34, 35, 37–39, 42, 43 | |
| Case Assessment | — | ||||||
| Cancer registry or medical records | 25 | 0.85 (0.75–0.97) | 39.81 | 42.2 | 0.016 | — | 8–12, 22–24, 26–31, 33–43 |
| Self report | 0 | N/A | N/A | N/A | N/A | N/A | |
| Study Population | 0.879 | ||||||
| Asians | 5 | 0.58 (0.34–0.96) | 10.86 | 63.2 | 0.028 | 22, 26, 27, 29, 40 | |
| Americans | 5 | 0.74 (0.62–0.88) | 1.62 | 0 | 0.806 | 10, 24, 28, 33, 41 | |
| Europeans | 13 | 0.89 (0.80–1.00) | 14.98 | 26.6 | 0.183 | 8, 9, 12, 23, 30, 31, 34, 35, 37–39, 42, 43 | |
| Cancer Grading | 0.103 | ||||||
| Invasive | 8 | 0.75 (0.58–0.95) | 13.42 | 47.8 | 0.063 | 10, 24, 26, 29, 30, 32, 33, 40 | |
| Borderline | 4 | 1.18 (0.82–1.70) | 0.33 | 0 | 0.954 | 31–33, 39 | |
| Cancer Histotype | 0.788 | ||||||
| Invasive serous | 2 | 1.01 (0.71–1.44) | 2.53 | 60.4 | 0.112 | 32, 33 | |
| Borderline serous | 2 | 0.81 (0.42–1.47) | 0.37 | 0 | 0.543 | 32, 33 | |
| Adjustment for confounders | |||||||
| Body mass index | 0.657 | ||||||
| Yes | 7 | 0.87 (0.77–0.97) | 5.95 | 15.9 | 0.311 | 8, 10, 11, 26, 27, 30, 31 | |
| No | 18 | 0.82 (0.68–0.99) | 33.78 | 49.7 | 0.009 | 9, 12, 22–24, 28, 29, 33–43 | |
| Parity | 0.167 | ||||||
| Yes | 17 | 0.83 (0.75–0.91) | 21.51 | 30.3 | 0.121 | 8, 9, 10, 22, 26, 28–31, 33–36, 38, 39, 40, 42 | |
| No | 8 | 1.09 (0.78–1.51) | 16.21 | 56.8 | 0.023 | 11, 12, 23, 24, 27, 37, 41, 43 | |
| OC use | 0.519 | ||||||
| Yes | 9 | 0.83 (0.74–0.92) | 2.97 | 0 | 0.888 | 8, 10, 28, 30, 31, 34, 35, 38, 39 | |
| No | 16 | 0.87 (0.69–1.09) | 35.96 | 58.3 | 0.002 | 9, 11, 12, 22–24, 26, 27, 29, 33, 36, 37, 40–43 | |
| Exogenous hormones use | 0.721 | ||||||
| Yes | 4 | 0.89 (0.76–1.05) | 0.34 | 0 | 0.845 | 8, 26, 30, 31 | |
| No | 21 | 0.84 (0.72–0.98) | 39.15 | 48.9 | 0.006 | 9–12, 22–24, 27–29, 33–43 | |
| Menopause status | 0.561 | ||||||
| Yes | 10 | 0.89 (0.79–1.01) | 5.85 | 0 | 0.670 | 8, 11, 26–28, 30, 31, 35, 39, 42 | |
| No | 15 | 0.81 (0.66–0.99) | 33.34 | 58.0 | 0.003 | 9, 10, 12, 22–24, 29, 33, 34, 36–38, 40, 41, 43 | |
| Smoking status | 0.911 | ||||||
| Yes | 6 | 0.84 (0.64–1.11) | 10.76 | 53.5 | 0.056 | 8, 11, 26–29 | |
| No | 19 | 0.86 (0.74–0.99) | 29.04 | 41.5 | 0.034 | 9, 10, 12 22–24, 30, 31, 33–43 | |
RR: relative risk; CI: confidence interval; OC: oral contraceptive.
*
P value for heterogeneity within each subgroup.
**
P value for heterogeneity between subgroups with meta-regression analysis.