Kyungdo Han

Cumulative abdominal obesity exposure and progressive risk of endometrial cancer in young women: a nationwide cohort study

The incidence of endometrial cancer has been rising sharply among younger generations, paralleling the growing obesity epidemic in this age group. Abdominal obesity is currently being investigated as an indicator of adiposity and cancer risk, and its prevalence is increasing in young women. This study aimed to examine whether cumulative abdominal obesity exposure in young women was associated with the development of endometrial cancer. We used data from the South Korean National Health Insurance Service for women aged 20-39 years who had completed four consecutive annual health examinations between 2009 and 2012 and had no history of cancer at baseline. Participants were categorized into five groups based on the number of abdominal obesity exposures (waist circumference ≥ 85 cm). Exposure numbers ranged from 0 to 4, indicating the frequency of abdominal obesity across the four health examinations over 4 years. The primary outcome was newly diagnosed endometrial cancer, which was monitored until 2020, with a follow-up period of 7.12 years. Among the 445,791 young women (mean [SD] age 30.82 [4.55] years), 302 (mean [SD], 32.79 [4.53] years) developed endometrial cancer. The cumulative incidence of endometrial cancer differed significantly according to the number of abdominal obesity exposures (log-rank test, P < .001). The incidence of endometrial cancer has progressively increased with abdominal obesity exposure. The multivariable-adjusted HRs for incident endometrial cancer were 1.480 (95% CI, 0.970-2.258), 2.361 (95% CI, 1.391-4.008), 4.114 (95% CI, 2.546-6.647), and 6.215 (95% CI, 4.250-9.088) for participants with exposure numbers of 1-4, respectively, compared with those with an exposure number of 0. In this population-based nationwide cohort study of young women, we observed a progressive increase in the risk of endometrial cancer with cumulative abdominal obesity exposure.

Impact of Changes in Obesity and Abdominal Obesity on Endometrial Cancer Risk in Young Korean Women: A Nationwide Cohort Study

Abstract Background: The increasing incidence of endometrial cancer in young women parallels the increasing prevalence of obesity, a well-established risk factor. However, the impact of longitudinal changes in obesity and abdominal obesity on early-onset endometrial cancer remains insufficiently understood. Methods: This nationwide cohort study utilized data from the Korean National Health Insurance Service. Women, ages 20 to 39 years, who underwent two health examinations at a 3-year interval between 2009 and 2015, with no history of cancer, were included. Participants were categorized based on changes in obesity (body mass index ≥25 kg/m2) or abdominal obesity (waist circumference ≥85 cm) into four groups: stable non-obese, non-obese to obese, obese to non-obese, and stable obese. The risk of endometrial cancer was assessed using Cox proportional hazards models. Results: Among 935,600 women, 798 developed endometrial cancer. Compared with the stable non-obese group, adjusted HRs for endometrial cancer were 1.940 (1.468–2.563), 2.083 (1.447–3.001), and 2.083 (1.447–3.001) in the non-obese to obese, obese to non-obese, and stable obese groups, respectively. With regard to abdominal obesity, the adjusted HRs were 2.048 (1.581–2.651), 2.302 (1.684–3.146), and 4.394 (3.557–5.427), respectively. The risk of cancer was higher in the obese to non-obese group than in the non-obese to obese group. Conclusions: Changes in obesity and abdominal obesity statuses were associated with early-onset endometrial cancer, with persistent abdominal obesity showing the highest risk. Impact: These findings support the need for early, sustained obesity interventions to reduce endometrial cancer risk in young women.