胃癌（GC）幸存者可能更容易患骨质疏松症。然而，很少有针对大量患者群体进行GC与骨质疏松症之间关系的研究。我们的目的是通过比较 GC 患者和使用韩国国民健康保险服务国家样本队列 (KNHIS-NSC) 的匹配对照患者来确定骨质疏松症的发病率并确定相关因素。这项研究包括 9078 名 GC 患者和 36,312 名对照者（性别、年龄、居住地和收入进行 1:4 倾向评分匹配）。根据查尔森合并症指数 (CCI) 评分调整模型（调整后的 HR = 1.13），GC 患者的骨质疏松风险比 (HR) 显着高于对照组。 Kaplan-Meier 分析显示，从索引日期开始的随访期内，GC 患者的骨质疏松累积发病率显着高于对照组 (p = 0.0087)。在年龄 < 65 岁、男性和 CCI 评分 = 0 的人群中，骨质疏松症与 GC 呈正相关。 总之，研究结果表明，年龄 < 65 岁的 GC 男性患骨质疏松症的风险可能增加。需要对其他危险因素和最佳干预时机进行研究，以预防胃癌幸存者骨折并尽量减少骨质流失。

Gastric cancer (GC) survivors may be more likely to develop osteoporosis. However, few studies on the relationship between GC and osteoporosis have been conducted on large patient populations. We aimed to determine the incidence of osteoporosis and identify related factors by comparing patients with GC and matched controls using the Korean National Health Insurance Service-National Sample Cohort (KNHIS-NSC). This study included 9078 patients with GC and 36,312 controls (1:4 propensity score-matched for sex, age, residence, and income). The hazard ratio (HR) for osteoporosis was significantly greater for GC patients than for controls according to Charlson Comorbidity Index (CCI) score-adjusted models (adjusted HR = 1.13). Kaplan-Meier analysis revealed that the cumulative incidence of osteoporosis during the follow-up period commencing from the index date was significantly greater in GC patients than in the controls (p = 0.0087). A positive correlation of osteoporosis with GC was detected for those aged < 65 years, males, and those with CCI scores = 0. In conclusion, the study findings suggest that men with GC aged < 65 years may be at an increased risk for osteoporosis. Research into additional risk factors and the optimal timing of interventions are needed to prevent fractures and minimize bone loss in GC survivors.