Early menarche and later menopause are associated with increased ovarian cancer risk

1. Across the premenopausal and postmenopausal groups, early menarche, later menopause, and longer reproductive span were associated with higher ovarian cancer risk, while parity was associated with lower risk of ovarian cancer. 

Evidence Rating Level: 2 (Good)

Although reproductive factors have been associated with ovarian cancer risk, it is unclear whether reproductive factor associations differ by menopausal status and birth cohorts. This study thus assessed the associations between reproductive factors and ovarian cancer risk across menopausal status and birth cohorts. This population-based cohort study used data from South Korea’s National Health Insurance Service (NHIS). Women aged >40 years who underwent NHIS health screening in 2009 were included and followed up until ovarian cancer diagnosis, death, or December 31, 2022. The primary outcome was incident ovarian cancer. In total, 2,285,774 women (932,637 [40.8%] premenopausal, 1, 353,137 [59.2%] postmenopausal; mean [SD] age, 54.9 [10.85] years) were included in the study. Over a mean (SD) follow-up duration of 10.7 (2.99) years, 10,729 ovarian cancer cases were identified. For both premenopausal women and postmenopausal women, early menarche (aged ≤12 vs >16 years) was associated with higher ovarian cancer risk (HR, 1.37; 95% CI, 1.16-1.61] and HR, 1.24; 95% CI, 1.00-1.54), while parity of >2 births was associated with lower ovarian cancer risk (HR, 0.68; 95% CI, 0.58-0.79 and HR, 0.71; 95% CI, 0.60-0.85]). Breastfeeding for >12 months and oral contraceptive use for >1 year were associated with lower ovarian cancer risk in premenopausal women (HR, 0.86; 95% CI, 0.77-0.96 and HR, 0.75; 95% CI, 0.61-0.93) but not postmenopausal women. Among postmenopausal women, later menopause (≥55 years; HR, 1.36; 95% CI, 1.11-1.66), longer reproductive span (≥40 years; HR, 1.21; 95% CI, 1.09-1.34), and hormone replacement therapy use for 2 to 5 years (HR, 1.20; 95% CI, 1.07-1.34) were associated with higher risk of ovarian cancer. Overall, this study found associations between reproductive factors and cancer risk that differed across menopausal status and birth cohorts, highlighting the need for tailored prevention interventions for these populations. 

Click here to read this study in JAMA Network Open

Image: PD

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