Table 1.
Summary of evidence grading for meta-analysis of risk factors associated with ovarian cancer incidence or mortality–cohort studies only *.
| Evidence | Criteria Used | Decreased Risk | Increased Risk |
|---|---|---|---|
| Strong |
p < 10−6 ||; >1000 cases; I2 < 50%; no small study effects ¶; prediction interval excludes the null value; no excess significance bias † n = 6 |
Past drug history OCP inc Ever vs. never ** |
Anthropometric measure Height inc Per 10 cm BMI; ≥30 kg/m2 vs. normal |
|
Past drug history HRT inc Ever vs. never (prospective studies) HRT inc Current/recent vs. never (prospective studies) HRT inc Ever vs. never (prospective studies; info duration of use and time since last use known) | |||
| Highly Suggestive |
p < 10−6 ||; >1000 cases; p < 0.05 of the largest study in a meta-analysis n = 3 |
Past drug history Metformin inc Ever vs. never |
Past drug history HRT inc Ever vs. never ET only |
|
Medical history Endometriosis inc Any vs. none | |||
| Suggestive |
p < 10−3 ||; >1000 cases n = 5 |
None |
Anthropometric measures BMI inc iya per 5 kg/m2 increase BMI inc per 5 kg/m2 increase |
|
Asbestos Any vs. none MO | |||
|
Medical history Diabetes inc; Yes vs. no | |||
|
Past drug history HRT inc; Current vs. ever | |||
| Weak |
p < 0.05 n = 26 |
Reproductive factors Breastfeeding inc; Per 5 mo increase in duration |
Anthropometric measures BMI inc PrMP Obese vs. normal BMI inc PoMP; Obese vs. normal Per 5 kg weight inc WG per 5 kg increase PoMP, HRT, inc |
|
Past drug history NSAIDS inc, Non aspirin; Ever vs. never OCP inc; Ever vs. never | |||
|
Medical history SLE inc; observed vs. expected |
Asbestos Total exposed vs. non-exposed, MO High exposed vs. non-exposed, MO |
||
|
Dietary Intake Tea (black) inc; Highest vs. lowest Non herbal tea inc; Highest vs. lowest Calcium inc; Highest vs. lowest Non-starchy vegetables inc; Per 100 g/day | |||
|
Dietary intake Dairy total inc; Highest vs. lowest Dairy skim/low fat inc; Highest vs. lowest Dairy lactose inc; Highest vs. lowest Meat (processed) inc; Highest vs. lowest Meat (red and processed) MO; Per 100 g/week increment | |||
|
Past drug history HRT inc; Ever vs. never (continuous E + P) HRT inc; Ever vs. never (sequential E + P) HRT inc; Ever vs. never (E + P) HRT inc; Ever vs. never (E + E/P) | |||
|
Reproductive Factors PID inc; Ever vs never IVF inc; Ever vs. never (reference group general population) IVF inc; Ever vs. never (reference group IVF population) |
(1) Abbreviations: BMI, body mass index; BMI iya, body mass index in young adulthood; BMI PrMP, body mass index premenopausal; CC, case control; HRT, hormone replacement therapy; inc, incidence; MO, mortality; NSAID, non-steroidal anti-inflammatory drugs; WG, weight gain; BMI PoMP, body mass index postmenopausal; CRP, c-reactive protein; OCP, oral contraceptive pill; SLE, systemic lupus erythematous; E + P, estrogen and progesterone; E + E/P, estrogen and estrogen/progesterone; PID, pelvic inflammatory disease; IVF, in-vitro fertilization; RR, relative risk. (2) Key: * only meta-analyses meeting at least weak grade of evidence listed. ** % reduction in the standard error. || p indicates the p-values of the meta-analysis random effects model. ¶ Small study effect is based on the p-value from the Egger’s regression asymmetry test (p > 0.1) where the random effects summary estimate was larger compared to the point estimate of the largest study in a meta-analysis. † Based on the p-value (p > 0.1) of the excess significance test using the largest study (smallest standard error) in a meta-analysis as the plausible effect size.