Different Patterns of the Relationship Between Gynecological Malignancy and Obesity Index: A Nationwide Retrospective...

In Korea, the patterns of prevalence of gynecological cancers have shifted due to rising obesity-related cancer cases. We evaluated the associations of body mass index (BMI) and waist circumference (WC) with the risk of gynecological malignancy in Korean women.

Using National Health Insurance Service cohort data, we analyzed 365,581 participants among the 1,999,980 women aged ≥ 19 years who underwent health check-ups at the baseline year 2009-2010, excluding those who died, those with prior cancer diagnoses, underwent hysterectomy and/or salpingo-oophorectomy before the index date (January 1st, 2011), or missing/outliers BMI and WC values. Follow-up extended to December 31st, 2021, evaluating the incidences of endometrial, ovarian, and cervical cancer. The hazard ratios (HRs) and 95% confidence intervals (CIs) for each gynecological malignancy according to BMI and WC were calculated using Cox proportional hazard regression.

Among the 365,581 participants, 898, 1,268, and 873 cases of endometrial, ovarian, and cervical cancer occurred, respectively. HRs (95% CIs) for endometrial cancer were 1.37 (1.15-1.63), 1.63 (1.38-1.94), and 3.64 (2.81-4.70) for BMIs of 23.0-24.9, 25.0-29.9, and ≥ 30 kg/m² compared to BMI of 18.5-22.9 kg/m² (P for trend < 0.001). HRs (95% CIs) for ovarian cancer were 1.16 (1.00-1.33), 1.19 (1.03-1.37), and 1.49 (1.12-1.98) for BMIs of 23.0-24.9, 25.0-29.9, and ≥ 30 kg/m² compared to BMI of 18.5-22.9 kg/m² (P for trend = 0.002). No significant association was found between BMI and the risk for cervical cancer (P for trend = 0.266). HRs (95% CIs) for endometrial cancer were 1.35 (1.09-1.66), 1.41 (1.14-1.74), and 1.90 (1.55-2.34) for the 2nd, 3rd, and 4th quartiles of WCs compared to the 1st quartile (P for trend <0.001). Ovarian cancer tended to increase and cervical cancer tended to decrease as WC increased (P for trend = 0.035 for ovarian cancer, P for trend = 0.034 for cervical cancer).

In Korean women, the risks of endometrial and ovarian cancers increased significantly from the pre-obese level as BMI and WC increased, while cervical cancer risk tended to increase as WC decreased. Management of obesity should be reinforced for the prevention of obesity-related gynecological cancers, considering the increasing incidence of these cancers among Korean women.