Age- and Sex-Specific Risks of Colorectal Cancers in Diabetic Patients

Age- and Sex-Specific Risks of Colorectal Cancers in Diabetic Patients

HUA-FEN CHEN,^1,2 PETER CHEN,³ YING-HWA SU,⁴ HUI-FANG SU⁵ and CHUNG-YI LI^6,7

¹Department of Endocrinology, Far Eastern Memorial Hospital, New Taipei City, Taiwan
²School of Medicine, Fujen Catholic University, New Taipei City, Taiwan
³Department of Gastroenterology, Central Medicine Hospital Group, New Taipei City, Taiwan
⁴Department of Nursing, College of Medicine, National Cheng Kung University, Tainan City, Taiwan
⁵Department of Health Care Management, National Taipei University of Nursing and Health Sciences, Taipei City, Taiwan
⁶Department and Graduate Institute of Public Health, College of Medicine, National Cheng Kung University, Tainan City, Taiwan
⁷Department of Public Health, College of Public Health, China Medical University, Taichung, Taiwan

Diabetes has been reported to increase the risk of colorectal neoplasm in most but not all studies. However, the data on age- and sex-specific incidence rates and relative risks associated with diabetes are limited. We carried out this population-based cohort study to investigate the overall sex- and age-specific risks of colorectal cancer in association with diabetes. Diabetic patients (n = 615,532) and age- and sex-matched control individuals (n = 614,871), selected from the claim datasets, were followed up from 2000 to 2006. The rates of admission due to colon and rectum cancers were estimated using the person-years approach, and the age- and sex-specific hazard ratio (HR) for both the malignancies were determined using the Cox regression model. The overall incidence rate of colon cancer was 9.94 per 10,000 patient-years for the diabetic patients, as opposed to 7.84 per 10,000 patient-years for the control-group patients. The corresponding observation for rectal cancer was 7.16 and 6.28 per 10,000 patient-years. Diabetic patients aged ≥ 45 years had significantly high HRs for developing colon cancer (1.20-1.45-fold). We also noted a significantly high HR of rectal cancer in diabetic men (1.18-fold) aged ≥ 45 years, but not in diabetic women. In conclusion, diabetes may significantly increase the risk of colorectal cancer, especially in patients aged 45-64 years. Diabetologists should keep this relationship in mind while treating middle-aged diabetic men and should also advise these patients to undergo regular screening tests for colorectal cancer.

keywords —— cohort studies; colonic neoplasm; diabetes mellitus; hazard ratio; rectal neoplasm

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Tohoku J. Exp. Med., 2012, 226, 259-265

Correspondence: Chung-Yi Li, Ph.D., Department and Graduate Institute of Public Health, College of Medicine, National Cheng Kung University, #1, University Rd., Tainan 701, Taiwan.

e-mail: cyli99@mail.ncku.edu.tw