Table 1.
Sociodemographic and clinical characteristics of early-onset colorectal cancer cases and controls aged 20–49 years, Ontario, Canada, 2018–2019
| Characteristics | Cases (n = 175) |
Controls (n = 253) |
Age- and sex-adjusted ORb (95% CI) | ||
|---|---|---|---|---|---|
|
na (%) |
na (%) |
||||
| Age, years | |||||
| Mean (SD) |
43.1 (5.6) |
40.1 (7.9) |
N/A | ||
| Age group, years | |||||
| 20–29 |
6 (3) |
36 (14) |
N/A | ||
| 30–34 |
11 (6) |
18 (7) |
|||
| 35–39 |
23 (13) |
35 (14) |
|||
| 40–44 |
38 (22) |
69 (27) |
|||
| 45–49 |
97 (55) |
95 (38) |
|||
| Sex | |||||
| Male |
74 (42) |
112 (44) |
N/A | ||
| Female |
101 (58) |
141 (56) |
|||
| Race/ethnicity | |||||
| White |
141 (81) |
202 (80) |
1.00 | ||
| East/Southeast Asian |
16 (9) |
16 (6) |
1.50 (0.71–3.15) | ||
| South Asian |
5 (3) |
16 (6) |
0.57 (0.20–1.66) | ||
| Otherc |
13 (7) |
17 (7) |
1.03 (0.48–2.21) | ||
| Country of birth | |||||
| Canada |
146 (83) |
184 (73) |
1.00 | ||
| Outside Canada |
29 (17) |
69 (27) |
0.51 (0.31–0.84) | ||
| Highest level of education | |||||
| High school graduate or less |
32 (18) |
46 (19) |
1.00 | ||
| College or university degree |
98 (56) |
138 (56) |
0.97 (0.57–1.66) | ||
| Post-graduate degree |
45 (26) |
64 (26) |
0.98 (0.54–1.80) | ||
| Annual household incomed, CAD$ | |||||
| < $30,000 |
9 (5) |
23 (10) |
1.00 | ||
| $30,000–$69,999 |
29 (18) |
44 (20) |
1.56 (0.62–3.93) | ||
| $70,000–$100,000 |
38 (23) |
46 (21) |
1.91 (0.77–4.70) | ||
| > $100,000 |
88 (54) |
108 (49) |
1.85 (0.80–4.29) | ||
| Unknown (prefer not to answer) | 11 | 32 | |||
| Occupationd | |||||
| Professionale |
63 (36) |
93 (37) |
1.00 | ||
| Managerial and Administrativef |
33 (19) |
41 (16) |
1.12 (0.63–1.98) | ||
| Sales and Servicesg |
25 (14) |
34 (13) |
1.11 (0.60–2.06) | ||
| Clericalh |
22 (13) |
21 (8) |
1.46 (0.73–2.94) | ||
| Manufacturing, Agriculture, and Tradesi |
17 (10) |
26 (10) |
1.08 (0.53–2.21) | ||
| Student/not employed |
7 (4) |
27 (11) |
0.53 (0.21–1.37) | ||
| Other/unspecified |
8 (5) |
11 (4) |
1.01 (0.38–2.67) | ||
| Usual residence during most of life | |||||
| Urban |
140 (81) |
202 (81) |
1.00 | ||
| Rural |
32 (19) |
47 (19) |
0.98 (0.59–1.63) | ||
| Anatomical subsitej | |||||
| Proximal colon |
41 (24) |
N/A | N/A | ||
| Distal colon |
49 (28) |
||||
| Rectum |
84 (48) |
||||
| MSI statusk | |||||
| Microsatellite stable or MSI-low |
122 (89) |
N/A | N/A | ||
| MSI-high |
15 (11) |
||||
| Unknown | 38 | ||||
| Stage at diagnosisl | |||||
| Stage I |
28 (19) |
N/A | N/A | ||
| Stage II |
30 (21) |
||||
| Stage III |
57 (39) |
||||
| Stage IV |
31 (21) |
||||
| Unknown | 29 | ||||
CAD Canadian Dollar; CI confidence interval; MSI microsatellite instability; N/A not applicable; OR odds ratio; SD standard deviation
aNumbers may not sum up to totals due to missing data. An “unknown” category is shown for variables with > 5% missing data
bAdjusted for age (continuous, years; age at diagnosis for cases and at questionnaire completion for controls) and sex
cIncludes Black (n = 9), Aboriginal (First Nations, Métis, or Inuit; n = 6), and other race/ethnicity (n = 15). Numbers broken down by case/control status are not shown due to small cell sizes
dTwo years ago
eProfessional occupations in natural and applied sciences, health, education, law and social, community and government services
fManagement, business, finance and administration occupations
gSales and service occupations, including occupations related to the hospitality and tourism industries
hAdministrative and office support occupations
iOccupations in manufacturing (e.g., metal, glass, chemicals, wood, pulp, textile), agriculture and natural resources (e.g., farming, fishing, forestry), construction, trades, transport and equipment operation
jBased on International Classification of Diseases for Oncology, 3rd Edition (ICD-O-3) topography codes (proximal colon: cecum [C18.0], ascending colon [C18.2], hepatic flexure of colon [C18.3], transverse colon [C18.4], and splenic flexure of colon [C18.5]; distal colon: descending colon [C18.6] and sigmoid colon [C18.7]; rectum: rectosigmoid junction [C19.9] and rectum, not otherwise specified [C20.9])
kBased on immunohistochemistry staining results for DNA mismatch repair proteins (MLH1, MSH2, MSH6, and PMS2). Cases were considered microsatellite stable or MSI-low if they had normal (intact) nuclear staining for all four proteins, else they were considered MSI-high if they had abnormal (deficient) staining for any of the four proteins
lDetermined based on multiple sources of staging information, including pathological staging and clinical staging (pathological stage was given priority where available), in accordance with the American Joint Committee on Cancer (AJCC) tumor-node-metastases (TNM) staging system, 8th Edition