Table 1 Study population characteristics at baseline
Colorectal cancer cohort (N = 20,340) | Matched controls (N = 100,058) | |||
|---|---|---|---|---|
Median follow-up (years), IQR | 3.65 (0.93–8.34) | 7.60 (4.26–11.49) | ||
Age at index date | ||||
Median | 73 | 72 | ||
IQR | 63–80 | 63–80 | ||
Minimum | 18 | 18 | ||
Maximum | 103 | 102 | ||
Calendar year of index date, n (%) | ||||
1997–1999 | 959 | (4.7) | 4,775 | (4.8) |
2000–2004 | 5,073 | (24.9) | 25,162 | (25.2) |
2005–2009 | 6,729 | (33.1) | 33,172 | (33.2) |
2010–2014 | 5,794 | (28.5) | 28,347 | (28.3) |
2015–2018 | 1,785 | (8.8) | 8,602 | (9.6) |
Sex, n (%) | ||||
Female | 9,253 | (45.5) | 45,598 | (45.6) |
Ethnicity, n (%) | ||||
White | 7,375 | (36.3) | 41,322 | (41.3) |
South Asian | 112 | (0.6) | 928 | (0.9) |
Black | 90 | (0.4) | 559 | (0.6) |
Other | 52 | (0.3) | 324 | (0.3) |
Mixed | 10 | (0.1) | 113 | (0.1) |
Unknown | 12,701 | (62.4) | 56,812 | (56.8) |
Index of Multiple Deprivation, n (%) | ||||
Quintile 1 (most deprived) | 4,874 | (24.0) | 24,297 | (24.3) |
Quintile 2 | 4,788 | (23.5) | 23,559 | (23.6) |
Quintile 3 | 4,318 | (21.2) | 21,213 | (21.2) |
Quintile 4 | 3,505 | (17.2) | 17,067 | (17.1) |
Quintile 5 (least deprived) | 2,833 | (14.0) | 13,829 | (13.8) |
Unknown | 22 | (0.1) | 93 | (0.1) |
Body Mass Index, Kg/m2, n (%) | ||||
Underweight (BMI < 18.5) | 442 | (2.2) | 1,763 | (1.8) |
Normal (BMI 18.5 to < 25) | 6,808 | (33.5) | 32,907 | (32.9) |
Pre-obesity (BMI 25.0 to < 30) | 7,171 | (35.3) | 36,173 | (36.2) |
Obesity class I (BMI 30 to < 35) | 2,844 | (14.0) | 14,000 | (14.0) |
Obesity class II (BMI 35 to < 40) | 814 | (4.0) | 3,973 | (4.0) |
Obesity class III (BMI ≥ 40) | 310 | (1.5) | 1,492 | (1.5) |
Unknown | 1,951 | (9.6) | 9,750 | (9.7) |
Smoking, n (%) | ||||
Never smoker | 8,385 | (41.2) | 44,304 | (44.3) |
Past smoker | 8,464 | (41.6) | 37,500 | (37.5) |
Current smoker | 3,020 | (14.9) | 15,407 | (15.4) |
Unknown | 471 | (2.3) | 2,847 | (2.9) |
Alcohol use, n (%) | ||||
Problem drinker | 2,401 | (11.8) | 9,976 | (10.0) |
Comorbidities, n (%) | ||||
At least one comorbidity | 11,861 | (58.3) | 53,803 | (53.8) |
Diabetes mellitus | 2,523 | (12.4) | 10,043 | (10.0) |
Cardiovascular disease | 6,775 | (33.3) | 31,048 | (31.0) |
Hypertension | 3,619 | (17.8) | 10,598 | (10.6) |
Autoimmune disease | 1,291 | (6.2) | 5,623 | (5.6) |
Rheumatoid arthritis | 320 | (1.6) | 1,570 | (1.6) |
Chronic kidney disease (CKD) stage 3-5a | 3,785 | (18.61) | 13,719 | (13.71) |