Abstract：
OBJECTIVE: The incidence of early-onset (<50 years of age) colorectal cancer (eoCRC) has been steadily increasing in high-income countries including Canada. Despite this increase in incidence, the etiology of eoCRC remains unclear and prospective cohort studies of potential risk factors are limited.
METHODS: We examined two prospective cohorts of healthy individuals (<50 years of age) who completed baseline questionnaires in the Ontario Health Study and Alberta\'s Tomorrow Project. We examined the associations between demographic characteristics, chronic health conditions, and lifestyle behaviours with the development of eoCRC using Cox proportional hazard models. Cohorts were analyzed separately and hazard ratios for each risk factor were pooled with random effects meta-analyses.
RESULTS: During an average follow-up of 6.63 years, 98 eoCRC cases occurred among study participants (n=127,852). A family history of CRC alone or with a history of other cancer types was associated with an increased risk of developing eoCRC (HR: 2.76, 95% CI: 1.43-5.32), but a family history of a non-CRC cancer only was not (HR: 1.18, 95% CI: 0.61-2.30). Heavy smokers (≥ 10 pack-years) at baseline had a higher risk of eoCRC compared to non-smokers (HR: 1.87, 95% CI: 1.00-3.52). Sex, socioeconomic factors, diabetes, alcohol consumption, among other factors were not significantly associated with the risk of eoCRC.
CONCLUSIONS: Our findings indicate that specific CRC risk factors are also associated with developing eoCRC. The data in the study offers valuable insights that could be integrated in future meta-analyses. Additional prospective cohort studies are required to understand the etiology of eoCRC.
METHODS: We examined two prospective cohorts of healthy individuals (<50 years of age) who completed baseline questionnaires in the Ontario Health Study and Alberta\'s Tomorrow Project. We examined the associations between demographic characteristics, chronic health conditions, and lifestyle behaviours with the development of eoCRC using Cox proportional hazard models. Cohorts were analyzed separately and hazard ratios for each risk factor were pooled with random effects meta-analyses.
RESULTS: During an average follow-up of 6.63 years, 98 eoCRC cases occurred among study participants (n=127,852). A family history of CRC alone or with a history of other cancer types was associated with an increased risk of developing eoCRC (HR: 2.76, 95% CI: 1.43-5.32), but a family history of a non-CRC cancer only was not (HR: 1.18, 95% CI: 0.61-2.30). Heavy smokers (≥ 10 pack-years) at baseline had a higher risk of eoCRC compared to non-smokers (HR: 1.87, 95% CI: 1.00-3.52). Sex, socioeconomic factors, diabetes, alcohol consumption, among other factors were not significantly associated with the risk of eoCRC.
CONCLUSIONS: Our findings indicate that specific CRC risk factors are also associated with developing eoCRC. The data in the study offers valuable insights that could be integrated in future meta-analyses. Additional prospective cohort studies are required to understand the etiology of eoCRC.
摘要：
目的：在包括加拿大在内的高收入国家，早发性（<50岁）结直肠癌（eoCRC）的发病率一直在稳步上升。尽管发病率有所增加，eoCRC的病因尚不清楚,潜在危险因素的前瞻性队列研究有限.
方法：我们研究了在安大略省健康研究和艾伯塔省明天项目中完成基线问卷的两个前瞻性健康个体（<50岁）队列。我们研究了人口统计学特征之间的关联，慢性健康状况,和生活方式行为随着eoCRC的发展使用Cox比例风险模型。分别对队列进行分析，并将每个风险因素的风险比与随机效应荟萃分析进行汇总。
结果：在平均6.63年的随访中，研究参与者中发生了98例eoCRC病例(n=127,852)。单独的CRC家族史或与其他癌症类型的病史与发展eoCRC的风险增加相关（HR：2.76，95％CI：1.43-5.32），但只有非CRC癌症家族史没有(HR:1.18,95%CI:0.61-2.30).与不吸烟者相比，基线时重度吸烟者（≥10包年）患eoCRC的风险更高（HR：1.87，95％CI：1.00-3.52）。性,社会经济因素,糖尿病,酒精消费,其他因素与eoCRC风险无显著相关.
结论：我们的研究结果表明，特定的CRC危险因素也与eoCRC的发展相关。研究中的数据提供了有价值的见解，可以整合到未来的荟萃分析中。需要更多的前瞻性队列研究来了解eoCRC的病因。
方法：我们研究了在安大略省健康研究和艾伯塔省明天项目中完成基线问卷的两个前瞻性健康个体（<50岁）队列。我们研究了人口统计学特征之间的关联，慢性健康状况,和生活方式行为随着eoCRC的发展使用Cox比例风险模型。分别对队列进行分析，并将每个风险因素的风险比与随机效应荟萃分析进行汇总。
结果：在平均6.63年的随访中，研究参与者中发生了98例eoCRC病例(n=127,852)。单独的CRC家族史或与其他癌症类型的病史与发展eoCRC的风险增加相关（HR：2.76，95％CI：1.43-5.32），但只有非CRC癌症家族史没有(HR:1.18,95%CI:0.61-2.30).与不吸烟者相比，基线时重度吸烟者（≥10包年）患eoCRC的风险更高（HR：1.87，95％CI：1.00-3.52）。性,社会经济因素,糖尿病,酒精消费,其他因素与eoCRC风险无显著相关.
结论：我们的研究结果表明，特定的CRC危险因素也与eoCRC的发展相关。研究中的数据提供了有价值的见解，可以整合到未来的荟萃分析中。需要更多的前瞻性队列研究来了解eoCRC的病因。
