Background & Aims

Colorectal cancer (CRC) incidence and mortality are increasing among persons younger than 50 years old in the United States, but risk factors associated with early-onset CRC (EOCRC) have not been widely studied.

Methods

We conducted a case-control study of US veterans 18 to 49 years old who underwent colonoscopy examinations from 1999 through 2014. EOCRC cases were identified from a national cancer registry; veterans who were free of CRC at their baseline colonoscopy through 3 years of follow-up were identified as controls. We collected data on age, sex, race/ethnicity, body weight, body mass index (BMI), diabetes, smoking status, and aspirin use. Multivariate-adjusted EOCRC odds were estimated for each factor, with corresponding 95% confidence interval (CI) values.

Results

Our final analysis included 651 EOCRC cases and 67,416 controls. Median age was 45.3 years, and 82.3% were male. Higher proportions of cases were older, male, current smokers, nonaspirin users, and had lower BMIs, compared with controls (P < .05). In adjusted analyses, increasing age and male sex were significantly associated with increased risk of EOCRC, whereas aspirin use and being overweight or obese (relative to normal BMI) were significantly associated with decreased odds of EOCRC. In post hoc analyses, weight loss of 5 kg or more within the 5-year period preceding colonoscopy was associated with higher odds of EOCRC (odds ratio 2.23; 95% CI 1.76–2.83).

Conclusions

In a case-control study of veterans, we found increasing age and male sex to be significantly associated with increased risk of EOCRC, and aspirin use to be significantly associated with decreased risk; these factors also affect risk for CRC onset after age 50. Weight loss may be an early clinical sign of EOCRC. More intense efforts are required to identify the factors that cause EOCRC and signs that can be used to identify individuals at highest risk.

中文翻译：

---

早发性结直肠癌的危险因素。

背景与目标

在美国，50 岁以下人群的结直肠癌 (CRC) 发病率和死亡率正在增加，但与早发性 CRC (EOCRC) 相关的风险因素尚未得到广泛研究。

方法

我们对 18 至 49 岁的美国退伍军人进行了一项病例对照研究，他们在 1999 年至 2014 年期间接受了结肠镜检查。EOCRC 病例来自国家癌症登记处；在基线结肠镜检查中通过 3 年的随访未患 CRC 的退伍军人被确定为对照。我们收集了有关年龄、性别、种族/民族、体重、体重指数 (BMI)、糖尿病、吸烟状况和阿司匹林使用情况的数据。估计每个因素的多变量调整后 EOCRC 几率，以及相应的 95% 置信区间 (CI) 值。

结果

我们的最终分析包括 651 例 EOCRC 病例和 67,416 例对照。中位年龄为 45.3 岁，82.3% 为男性。与对照组相比，老年人、男性、目前吸烟者、非阿司匹林使用者以及 BMI 较低的病例比例较高 ( P < .05)。在调整后的分析中，年龄和男性的增加与 EOCRC 的风险增加显着相关，而阿司匹林的使用和超重或肥胖（相对于正常 BMI）与 EOCRC 的几率降低显着相关。在事后分析中，结肠镜检查前 5 年内体重减轻 5 kg 或更多与 EOCRC 的较高几率相关（优势比 2.23；95% CI 1.76–2.83）。

结论

在退伍军人的病例对照研究中，我们发现年龄和男性的增加与 EOCRC 的风险增加显着相关，而阿司匹林的使用与风险降低显着相关；这些因素也会影响 50 岁后 CRC 发病的风险。体重减轻可能是 EOCRC 的早期临床症状。需要更加努力地确定导致 EOCRC 的因素和可用于识别最高风险个体的迹象。