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

Abstract

Background: 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.

Methods: 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.

Results: 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).

Conclusion: 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.